Huáng Jùnliàng 8478027d1a
Make sure babel parser throws exactly same recoverable errors when estree plugin is enabled (#12375)
* refactor: introduce isPrivateName and getPrivateNameSV

* feat: check recoverable errors on estree-throw

* fix: pass through all params of parseBlockBody

* fix: set bigInt to null when invalid bigInt value is parsed

e.g. 0.1n

* fix: use string literal value in error message

When estree plugin is enabled, stringLiteral#extra.raw is not accessible. Use StringLiteral#value instead.

* refactor: introduce hasPropertyAsPrivateName

* fix: adapt to ChainExpression

* fix: port checkLVal early return for method in object pattern

* fix: throw new a?.() on estree

* fix: early return for __proto__ in accessors

* fix: test record element via isObjectProperty

* fix: pass through isLHS in toAssignable

* refactor: introduce isObjectMethod methods
2020-12-03 08:36:54 +00:00

2615 lines
78 KiB
JavaScript

// @flow
// A recursive descent parser operates by defining functions for all
// syntactic elements, and recursively calling those, each function
// advancing the input stream and returning an AST node. Precedence
// of constructs (for example, the fact that `!x[1]` means `!(x[1])`
// instead of `(!x)[1]` is handled by the fact that the parser
// function that parses unary prefix operators is called first, and
// in turn calls the function that parses `[]` subscripts — that
// way, it'll receive the node for `x[1]` already parsed, and wraps
// *that* in the unary operator node.
//
// Acorn uses an [operator precedence parser][opp] to handle binary
// operator precedence, because it is much more compact than using
// the technique outlined above, which uses different, nesting
// functions to specify precedence, for all of the ten binary
// precedence levels that JavaScript defines.
//
// [opp]: http://en.wikipedia.org/wiki/Operator-precedence_parser
import { types as tt, type TokenType } from "../tokenizer/types";
import { types as ct } from "../tokenizer/context";
import * as N from "../types";
import LValParser from "./lval";
import {
isKeyword,
isReservedWord,
isStrictReservedWord,
isStrictBindReservedWord,
isIdentifierStart,
} from "../util/identifier";
import type { Pos, Position } from "../util/location";
import * as charCodes from "charcodes";
import {
BIND_OUTSIDE,
BIND_VAR,
SCOPE_ARROW,
SCOPE_CLASS,
SCOPE_DIRECT_SUPER,
SCOPE_FUNCTION,
SCOPE_SUPER,
SCOPE_PROGRAM,
} from "../util/scopeflags";
import { ExpressionErrors } from "./util";
import {
PARAM_AWAIT,
PARAM_IN,
PARAM_RETURN,
PARAM,
functionFlags,
} from "../util/production-parameter";
import {
newArrowHeadScope,
newAsyncArrowScope,
newExpressionScope,
} from "../util/expression-scope.js";
import { Errors } from "./error";
export default class ExpressionParser extends LValParser {
// Forward-declaration: defined in statement.js
/*::
+parseBlock: (
allowDirectives?: boolean,
createNewLexicalScope?: boolean,
afterBlockParse?: (hasStrictModeDirective: boolean) => void,
) => N.BlockStatement;
+parseClass: (
node: N.Class,
isStatement: boolean,
optionalId?: boolean,
) => N.Class;
+parseDecorators: (allowExport?: boolean) => void;
+parseFunction: <T: N.NormalFunction>(
node: T,
statement?: number,
allowExpressionBody?: boolean,
isAsync?: boolean,
) => T;
+parseFunctionParams: (node: N.Function, allowModifiers?: boolean) => void;
+takeDecorators: (node: N.HasDecorators) => void;
*/
// For object literal, check if property __proto__ has been used more than once.
// If the expression is a destructuring assignment, then __proto__ may appear
// multiple times. Otherwise, __proto__ is a duplicated key.
// For record expression, check if property __proto__ exists
checkProto(
prop: N.ObjectMember | N.SpreadElement,
isRecord: boolean,
protoRef: { used: boolean },
refExpressionErrors: ?ExpressionErrors,
): void {
if (
prop.type === "SpreadElement" ||
this.isObjectMethod(prop) ||
prop.computed ||
// $FlowIgnore
prop.shorthand
) {
return;
}
const key = prop.key;
// It is either an Identifier or a String/NumericLiteral
const name = key.type === "Identifier" ? key.name : key.value;
if (name === "__proto__") {
if (isRecord) {
this.raise(key.start, Errors.RecordNoProto);
return;
}
if (protoRef.used) {
if (refExpressionErrors) {
// Store the first redefinition's position, otherwise ignore because
// we are parsing ambiguous pattern
if (refExpressionErrors.doubleProto === -1) {
refExpressionErrors.doubleProto = key.start;
}
} else {
this.raise(key.start, Errors.DuplicateProto);
}
}
protoRef.used = true;
}
}
shouldExitDescending(expr: N.Expression, potentialArrowAt: number): boolean {
return (
expr.type === "ArrowFunctionExpression" && expr.start === potentialArrowAt
);
}
// Convenience method to parse an Expression only
getExpression(): N.Expression {
let paramFlags = PARAM;
if (this.hasPlugin("topLevelAwait") && this.inModule) {
paramFlags |= PARAM_AWAIT;
}
this.scope.enter(SCOPE_PROGRAM);
this.prodParam.enter(paramFlags);
this.nextToken();
const expr = this.parseExpression();
if (!this.match(tt.eof)) {
this.unexpected();
}
expr.comments = this.state.comments;
expr.errors = this.state.errors;
return expr;
}
// ### Expression parsing
// These nest, from the most general expression type at the top to
// 'atomic', nondivisible expression types at the bottom. Most of
// the functions will simply let the function (s) below them parse,
// and, *if* the syntactic construct they handle is present, wrap
// the AST node that the inner parser gave them in another node.
// Parse a full expression.
// - `disallowIn`
// is used to forbid the `in` operator (in for loops initialization expressions)
// When `disallowIn` is true, the production parameter [In] is not present.
// - `refExpressionErrors `
// provides reference for storing '=' operator inside shorthand
// property assignment in contexts where both object expression
// and object pattern might appear (so it's possible to raise
// delayed syntax error at correct position).
parseExpression(
disallowIn?: boolean,
refExpressionErrors?: ExpressionErrors,
): N.Expression {
if (disallowIn) {
return this.disallowInAnd(() =>
this.parseExpressionBase(refExpressionErrors),
);
}
return this.allowInAnd(() => this.parseExpressionBase(refExpressionErrors));
}
// https://tc39.es/ecma262/#prod-Expression
parseExpressionBase(refExpressionErrors?: ExpressionErrors): N.Expression {
const startPos = this.state.start;
const startLoc = this.state.startLoc;
const expr = this.parseMaybeAssign(refExpressionErrors);
if (this.match(tt.comma)) {
const node = this.startNodeAt(startPos, startLoc);
node.expressions = [expr];
while (this.eat(tt.comma)) {
node.expressions.push(this.parseMaybeAssign(refExpressionErrors));
}
this.toReferencedList(node.expressions);
return this.finishNode(node, "SequenceExpression");
}
return expr;
}
// Set [~In] parameter for assignment expression
parseMaybeAssignDisallowIn(
refExpressionErrors?: ?ExpressionErrors,
afterLeftParse?: Function,
refNeedsArrowPos?: ?Pos,
) {
return this.disallowInAnd(() =>
this.parseMaybeAssign(
refExpressionErrors,
afterLeftParse,
refNeedsArrowPos,
),
);
}
// Set [+In] parameter for assignment expression
parseMaybeAssignAllowIn(
refExpressionErrors?: ?ExpressionErrors,
afterLeftParse?: Function,
refNeedsArrowPos?: ?Pos,
) {
return this.allowInAnd(() =>
this.parseMaybeAssign(
refExpressionErrors,
afterLeftParse,
refNeedsArrowPos,
),
);
}
// Parse an assignment expression. This includes applications of
// operators like `+=`.
// https://tc39.es/ecma262/#prod-AssignmentExpression
parseMaybeAssign(
refExpressionErrors?: ?ExpressionErrors,
afterLeftParse?: Function,
refNeedsArrowPos?: ?Pos,
): N.Expression {
const startPos = this.state.start;
const startLoc = this.state.startLoc;
if (this.isContextual("yield")) {
if (this.prodParam.hasYield) {
// If we have [Yield] production, `yield` will start a YieldExpression thus
// regex is allowed following. Otherwise `yield` is an identifier and regex
// is disallowed in tt.name.updateContext
this.state.exprAllowed = true;
let left = this.parseYield();
if (afterLeftParse) {
left = afterLeftParse.call(this, left, startPos, startLoc);
}
return left;
}
}
let ownExpressionErrors;
if (refExpressionErrors) {
ownExpressionErrors = false;
} else {
refExpressionErrors = new ExpressionErrors();
ownExpressionErrors = true;
}
if (this.match(tt.parenL) || this.match(tt.name)) {
this.state.potentialArrowAt = this.state.start;
}
let left = this.parseMaybeConditional(
refExpressionErrors,
refNeedsArrowPos,
);
if (afterLeftParse) {
left = afterLeftParse.call(this, left, startPos, startLoc);
}
if (this.state.type.isAssign) {
const node = this.startNodeAt(startPos, startLoc);
const operator = this.state.value;
node.operator = operator;
if (this.match(tt.eq)) {
node.left = this.toAssignable(left, /* isLHS */ true);
refExpressionErrors.doubleProto = -1; // reset because double __proto__ is valid in assignment expression
} else {
node.left = left;
}
if (refExpressionErrors.shorthandAssign >= node.left.start) {
refExpressionErrors.shorthandAssign = -1; // reset because shorthand default was used correctly
}
this.checkLVal(left, "assignment expression");
this.next();
node.right = this.parseMaybeAssign();
return this.finishNode(node, "AssignmentExpression");
} else if (ownExpressionErrors) {
this.checkExpressionErrors(refExpressionErrors, true);
}
return left;
}
// Parse a ternary conditional (`?:`) operator.
// https://tc39.es/ecma262/#prod-ConditionalExpression
parseMaybeConditional(
refExpressionErrors: ExpressionErrors,
refNeedsArrowPos?: ?Pos,
): N.Expression {
const startPos = this.state.start;
const startLoc = this.state.startLoc;
const potentialArrowAt = this.state.potentialArrowAt;
const expr = this.parseExprOps(refExpressionErrors);
if (this.shouldExitDescending(expr, potentialArrowAt)) {
return expr;
}
return this.parseConditional(expr, startPos, startLoc, refNeedsArrowPos);
}
parseConditional(
expr: N.Expression,
startPos: number,
startLoc: Position,
// FIXME: Disabling this for now since can't seem to get it to play nicely
// eslint-disable-next-line no-unused-vars
refNeedsArrowPos?: ?Pos,
): N.Expression {
if (this.eat(tt.question)) {
const node = this.startNodeAt(startPos, startLoc);
node.test = expr;
node.consequent = this.parseMaybeAssignAllowIn();
this.expect(tt.colon);
node.alternate = this.parseMaybeAssign();
return this.finishNode(node, "ConditionalExpression");
}
return expr;
}
// Start the precedence parser.
// https://tc39.es/ecma262/#prod-ShortCircuitExpression
parseExprOps(refExpressionErrors: ExpressionErrors): N.Expression {
const startPos = this.state.start;
const startLoc = this.state.startLoc;
const potentialArrowAt = this.state.potentialArrowAt;
const expr = this.parseMaybeUnary(refExpressionErrors);
if (this.shouldExitDescending(expr, potentialArrowAt)) {
return expr;
}
return this.parseExprOp(expr, startPos, startLoc, -1);
}
// Parse binary operators with the operator precedence parsing
// algorithm. `left` is the left-hand side of the operator.
// `minPrec` provides context that allows the function to stop and
// defer further parser to one of its callers when it encounters an
// operator that has a lower precedence than the set it is parsing.
parseExprOp(
left: N.Expression,
leftStartPos: number,
leftStartLoc: Position,
minPrec: number,
): N.Expression {
let prec = this.state.type.binop;
if (prec != null && (this.prodParam.hasIn || !this.match(tt._in))) {
if (prec > minPrec) {
const op = this.state.type;
if (op === tt.pipeline) {
this.expectPlugin("pipelineOperator");
if (this.state.inFSharpPipelineDirectBody) {
return left;
}
this.state.inPipeline = true;
this.checkPipelineAtInfixOperator(left, leftStartPos);
}
const node = this.startNodeAt(leftStartPos, leftStartLoc);
node.left = left;
node.operator = this.state.value;
if (
op === tt.exponent &&
left.type === "UnaryExpression" &&
(this.options.createParenthesizedExpressions ||
!(left.extra && left.extra.parenthesized))
) {
this.raise(
left.argument.start,
Errors.UnexpectedTokenUnaryExponentiation,
);
}
const logical = op === tt.logicalOR || op === tt.logicalAND;
const coalesce = op === tt.nullishCoalescing;
if (coalesce) {
// Handle the precedence of `tt.coalesce` as equal to the range of logical expressions.
// In other words, `node.right` shouldn't contain logical expressions in order to check the mixed error.
prec = ((tt.logicalAND: any): { binop: number }).binop;
}
this.next();
if (
op === tt.pipeline &&
this.getPluginOption("pipelineOperator", "proposal") === "minimal"
) {
if (
this.match(tt.name) &&
this.state.value === "await" &&
this.prodParam.hasAwait
) {
throw this.raise(
this.state.start,
Errors.UnexpectedAwaitAfterPipelineBody,
);
}
}
node.right = this.parseExprOpRightExpr(op, prec);
this.finishNode(
node,
logical || coalesce ? "LogicalExpression" : "BinaryExpression",
);
/* this check is for all ?? operators
* a ?? b && c for this example
* when op is coalesce and nextOp is logical (&&), throw at the pos of nextOp that it can not be mixed.
* Symmetrically it also throws when op is logical and nextOp is coalesce
*/
const nextOp = this.state.type;
if (
(coalesce && (nextOp === tt.logicalOR || nextOp === tt.logicalAND)) ||
(logical && nextOp === tt.nullishCoalescing)
) {
throw this.raise(this.state.start, Errors.MixingCoalesceWithLogical);
}
return this.parseExprOp(node, leftStartPos, leftStartLoc, minPrec);
}
}
return left;
}
// Helper function for `parseExprOp`. Parse the right-hand side of binary-
// operator expressions, then apply any operator-specific functions.
parseExprOpRightExpr(op: TokenType, prec: number): N.Expression {
const startPos = this.state.start;
const startLoc = this.state.startLoc;
switch (op) {
case tt.pipeline:
switch (this.getPluginOption("pipelineOperator", "proposal")) {
case "smart":
return this.withTopicPermittingContext(() => {
return this.parseSmartPipelineBody(
this.parseExprOpBaseRightExpr(op, prec),
startPos,
startLoc,
);
});
case "fsharp":
return this.withSoloAwaitPermittingContext(() => {
return this.parseFSharpPipelineBody(prec);
});
}
// falls through
default:
return this.parseExprOpBaseRightExpr(op, prec);
}
}
// Helper function for `parseExprOpRightExpr`. Parse the right-hand side of
// binary-operator expressions without applying any operator-specific functions.
parseExprOpBaseRightExpr(op: TokenType, prec: number): N.Expression {
const startPos = this.state.start;
const startLoc = this.state.startLoc;
return this.parseExprOp(
this.parseMaybeUnary(),
startPos,
startLoc,
op.rightAssociative ? prec - 1 : prec,
);
}
// Parse unary operators, both prefix and postfix.
// https://tc39.es/ecma262/#prod-UnaryExpression
parseMaybeUnary(refExpressionErrors: ?ExpressionErrors): N.Expression {
if (this.isContextual("await") && this.isAwaitAllowed()) {
return this.parseAwait();
}
const update = this.match(tt.incDec);
const node = this.startNode();
if (this.state.type.prefix) {
node.operator = this.state.value;
node.prefix = true;
if (this.match(tt._throw)) {
this.expectPlugin("throwExpressions");
}
const isDelete = this.match(tt._delete);
this.next();
node.argument = this.parseMaybeUnary();
this.checkExpressionErrors(refExpressionErrors, true);
if (this.state.strict && isDelete) {
const arg = node.argument;
if (arg.type === "Identifier") {
this.raise(node.start, Errors.StrictDelete);
} else if (this.hasPropertyAsPrivateName(arg)) {
this.raise(node.start, Errors.DeletePrivateField);
}
}
if (!update) {
return this.finishNode(node, "UnaryExpression");
}
}
return this.parseUpdate(node, update, refExpressionErrors);
}
// https://tc39.es/ecma262/#prod-UpdateExpression
parseUpdate(
node: N.Expression,
update: boolean,
refExpressionErrors: ?ExpressionErrors,
): N.Expression {
if (update) {
this.checkLVal(node.argument, "prefix operation");
return this.finishNode(node, "UpdateExpression");
}
const startPos = this.state.start;
const startLoc = this.state.startLoc;
let expr = this.parseExprSubscripts(refExpressionErrors);
if (this.checkExpressionErrors(refExpressionErrors, false)) return expr;
while (this.state.type.postfix && !this.canInsertSemicolon()) {
const node = this.startNodeAt(startPos, startLoc);
node.operator = this.state.value;
node.prefix = false;
node.argument = expr;
this.checkLVal(expr, "postfix operation");
this.next();
expr = this.finishNode(node, "UpdateExpression");
}
return expr;
}
// Parse call, dot, and `[]`-subscript expressions.
// https://tc39.es/ecma262/#prod-LeftHandSideExpression
parseExprSubscripts(refExpressionErrors: ?ExpressionErrors): N.Expression {
const startPos = this.state.start;
const startLoc = this.state.startLoc;
const potentialArrowAt = this.state.potentialArrowAt;
const expr = this.parseExprAtom(refExpressionErrors);
if (this.shouldExitDescending(expr, potentialArrowAt)) {
return expr;
}
return this.parseSubscripts(expr, startPos, startLoc);
}
parseSubscripts(
base: N.Expression,
startPos: number,
startLoc: Position,
noCalls?: ?boolean,
): N.Expression {
const state = {
optionalChainMember: false,
maybeAsyncArrow: this.atPossibleAsyncArrow(base),
stop: false,
};
do {
base = this.parseSubscript(base, startPos, startLoc, noCalls, state);
// After parsing a subscript, this isn't "async" for sure.
state.maybeAsyncArrow = false;
} while (!state.stop);
return base;
}
/**
* @param state Set 'state.stop = true' to indicate that we should stop parsing subscripts.
* state.optionalChainMember to indicate that the member is currently in OptionalChain
*/
parseSubscript(
base: N.Expression,
startPos: number,
startLoc: Position,
noCalls: ?boolean,
state: N.ParseSubscriptState,
): N.Expression {
if (!noCalls && this.eat(tt.doubleColon)) {
return this.parseBind(base, startPos, startLoc, noCalls, state);
} else if (this.match(tt.backQuote)) {
return this.parseTaggedTemplateExpression(
base,
startPos,
startLoc,
state,
);
}
let optional = false;
if (this.match(tt.questionDot)) {
if (noCalls && this.lookaheadCharCode() === charCodes.leftParenthesis) {
// stop at `?.` when parsing `new a?.()`
state.stop = true;
return base;
}
state.optionalChainMember = optional = true;
this.next();
}
if (!noCalls && this.match(tt.parenL)) {
return this.parseCoverCallAndAsyncArrowHead(
base,
startPos,
startLoc,
state,
optional,
);
} else if (optional || this.match(tt.bracketL) || this.eat(tt.dot)) {
return this.parseMember(base, startPos, startLoc, state, optional);
} else {
state.stop = true;
return base;
}
}
// base[?Yield, ?Await] [ Expression[+In, ?Yield, ?Await] ]
// base[?Yield, ?Await] . IdentifierName
// base[?Yield, ?Await] . PrivateIdentifier
// where `base` is one of CallExpression, MemberExpression and OptionalChain
parseMember(
base: N.Expression,
startPos: number,
startLoc: Position,
state: N.ParseSubscriptState,
optional: boolean,
): N.OptionalMemberExpression | N.MemberExpression {
const node = this.startNodeAt(startPos, startLoc);
const computed = this.eat(tt.bracketL);
node.object = base;
node.computed = computed;
const property = computed
? this.parseExpression()
: this.parseMaybePrivateName(true);
if (this.isPrivateName(property)) {
if (node.object.type === "Super") {
this.raise(startPos, Errors.SuperPrivateField);
}
this.classScope.usePrivateName(
this.getPrivateNameSV(property),
property.start,
);
}
node.property = property;
if (computed) {
this.expect(tt.bracketR);
}
if (state.optionalChainMember) {
node.optional = optional;
return this.finishNode(node, "OptionalMemberExpression");
} else {
return this.finishNode(node, "MemberExpression");
}
}
// https://github.com/tc39/proposal-bind-operator#syntax
parseBind(
base: N.Expression,
startPos: number,
startLoc: Position,
noCalls: ?boolean,
state: N.ParseSubscriptState,
): N.Expression {
const node = this.startNodeAt(startPos, startLoc);
node.object = base;
node.callee = this.parseNoCallExpr();
state.stop = true;
return this.parseSubscripts(
this.finishNode(node, "BindExpression"),
startPos,
startLoc,
noCalls,
);
}
// https://tc39.es/ecma262/#prod-CoverCallExpressionAndAsyncArrowHead
// CoverCallExpressionAndAsyncArrowHead
// CallExpression[?Yield, ?Await] Arguments[?Yield, ?Await]
// OptionalChain[?Yield, ?Await] Arguments[?Yield, ?Await]
parseCoverCallAndAsyncArrowHead(
base: N.Expression,
startPos: number,
startLoc: Position,
state: N.ParseSubscriptState,
optional: boolean,
): N.Expression {
const oldMaybeInArrowParameters = this.state.maybeInArrowParameters;
this.state.maybeInArrowParameters = true;
this.next(); // eat `(`
let node = this.startNodeAt(startPos, startLoc);
node.callee = base;
if (state.maybeAsyncArrow) {
this.expressionScope.enter(newAsyncArrowScope());
}
if (state.optionalChainMember) {
node.optional = optional;
}
if (optional) {
node.arguments = this.parseCallExpressionArguments(tt.parenR, false);
} else {
node.arguments = this.parseCallExpressionArguments(
tt.parenR,
state.maybeAsyncArrow,
base.type === "Import",
base.type !== "Super",
node,
);
}
this.finishCallExpression(node, state.optionalChainMember);
if (state.maybeAsyncArrow && this.shouldParseAsyncArrow() && !optional) {
state.stop = true;
this.expressionScope.validateAsPattern();
this.expressionScope.exit();
node = this.parseAsyncArrowFromCallExpression(
this.startNodeAt(startPos, startLoc),
node,
);
} else {
if (state.maybeAsyncArrow) {
this.expressionScope.exit();
}
this.toReferencedArguments(node);
}
this.state.maybeInArrowParameters = oldMaybeInArrowParameters;
return node;
}
toReferencedArguments(
node: N.CallExpression | N.OptionalCallExpression,
isParenthesizedExpr?: boolean,
) {
this.toReferencedListDeep(node.arguments, isParenthesizedExpr);
}
// MemberExpression [?Yield, ?Await] TemplateLiteral[?Yield, ?Await, +Tagged]
// CallExpression [?Yield, ?Await] TemplateLiteral[?Yield, ?Await, +Tagged]
parseTaggedTemplateExpression(
base: N.Expression,
startPos: number,
startLoc: Position,
state: N.ParseSubscriptState,
): N.TaggedTemplateExpression {
const node: N.TaggedTemplateExpression = this.startNodeAt(
startPos,
startLoc,
);
node.tag = base;
node.quasi = this.parseTemplate(true);
if (state.optionalChainMember) {
this.raise(startPos, Errors.OptionalChainingNoTemplate);
}
return this.finishNode(node, "TaggedTemplateExpression");
}
atPossibleAsyncArrow(base: N.Expression): boolean {
return (
base.type === "Identifier" &&
base.name === "async" &&
this.state.lastTokEnd === base.end &&
!this.canInsertSemicolon() &&
// check there are no escape sequences, such as \u{61}sync
base.end - base.start === 5 &&
base.start === this.state.potentialArrowAt
);
}
finishCallExpression<T: N.CallExpression | N.OptionalCallExpression>(
node: T,
optional: boolean,
): N.Expression {
if (node.callee.type === "Import") {
if (node.arguments.length === 2) {
// todo(Babel 8): remove the if condition,
// moduleAttributes is renamed to importAssertions
if (!this.hasPlugin("moduleAttributes")) {
this.expectPlugin("importAssertions");
}
}
if (node.arguments.length === 0 || node.arguments.length > 2) {
this.raise(
node.start,
Errors.ImportCallArity,
this.hasPlugin("importAssertions") ||
this.hasPlugin("moduleAttributes")
? "one or two arguments"
: "one argument",
);
} else {
for (const arg of node.arguments) {
if (arg.type === "SpreadElement") {
this.raise(arg.start, Errors.ImportCallSpreadArgument);
}
}
}
}
return this.finishNode(
node,
optional ? "OptionalCallExpression" : "CallExpression",
);
}
parseCallExpressionArguments(
close: TokenType,
possibleAsyncArrow: boolean,
dynamicImport?: boolean,
allowPlaceholder?: boolean,
nodeForExtra?: ?N.Node,
): $ReadOnlyArray<?N.Expression> {
const elts = [];
let first = true;
const oldInFSharpPipelineDirectBody = this.state.inFSharpPipelineDirectBody;
this.state.inFSharpPipelineDirectBody = false;
while (!this.eat(close)) {
if (first) {
first = false;
} else {
this.expect(tt.comma);
if (this.match(close)) {
if (
dynamicImport &&
!this.hasPlugin("importAssertions") &&
!this.hasPlugin("moduleAttributes")
) {
this.raise(
this.state.lastTokStart,
Errors.ImportCallArgumentTrailingComma,
);
}
if (nodeForExtra) {
this.addExtra(
nodeForExtra,
"trailingComma",
this.state.lastTokStart,
);
}
this.next();
break;
}
}
elts.push(
this.parseExprListItem(
false,
possibleAsyncArrow ? new ExpressionErrors() : undefined,
possibleAsyncArrow ? { start: 0 } : undefined,
allowPlaceholder,
),
);
}
this.state.inFSharpPipelineDirectBody = oldInFSharpPipelineDirectBody;
return elts;
}
shouldParseAsyncArrow(): boolean {
return this.match(tt.arrow) && !this.canInsertSemicolon();
}
parseAsyncArrowFromCallExpression(
node: N.ArrowFunctionExpression,
call: N.CallExpression,
): N.ArrowFunctionExpression {
this.expect(tt.arrow);
this.parseArrowExpression(
node,
call.arguments,
true,
call.extra?.trailingComma,
);
return node;
}
// Parse a no-call expression (like argument of `new` or `::` operators).
// https://tc39.es/ecma262/#prod-MemberExpression
parseNoCallExpr(): N.Expression {
const startPos = this.state.start;
const startLoc = this.state.startLoc;
return this.parseSubscripts(this.parseExprAtom(), startPos, startLoc, true);
}
// Parse an atomic expression — either a single token that is an
// expression, an expression started by a keyword like `function` or
// `new`, or an expression wrapped in punctuation like `()`, `[]`,
// or `{}`.
// https://tc39.es/ecma262/#prod-PrimaryExpression
// https://tc39.es/ecma262/#prod-AsyncArrowFunction
// PrimaryExpression
// Super
// Import
// AsyncArrowFunction
parseExprAtom(refExpressionErrors?: ?ExpressionErrors): N.Expression {
// If a division operator appears in an expression position, the
// tokenizer got confused, and we force it to read a regexp instead.
if (this.state.type === tt.slash) this.readRegexp();
const canBeArrow = this.state.potentialArrowAt === this.state.start;
let node;
switch (this.state.type) {
case tt._super:
return this.parseSuper();
case tt._import:
node = this.startNode();
this.next();
if (this.match(tt.dot)) {
return this.parseImportMetaProperty(node);
}
if (!this.match(tt.parenL)) {
this.raise(this.state.lastTokStart, Errors.UnsupportedImport);
}
return this.finishNode(node, "Import");
case tt._this:
node = this.startNode();
this.next();
return this.finishNode(node, "ThisExpression");
case tt.name: {
const containsEsc = this.state.containsEsc;
const id = this.parseIdentifier();
if (!containsEsc && id.name === "async" && !this.canInsertSemicolon()) {
if (this.match(tt._function)) {
const last = this.state.context.length - 1;
if (this.state.context[last] !== ct.functionStatement) {
// Since "async" is an identifier and normally identifiers
// can't be followed by expression, the tokenizer assumes
// that "function" starts a statement.
// Fixing it in the tokenizer would mean tracking not only the
// previous token ("async"), but also the one before to know
// its beforeExpr value.
// It's easier and more efficient to adjust the context here.
throw new Error("Internal error");
}
this.state.context[last] = ct.functionExpression;
this.next();
return this.parseFunction(
this.startNodeAtNode(id),
undefined,
true,
);
} else if (this.match(tt.name)) {
return this.parseAsyncArrowUnaryFunction(id);
}
}
if (canBeArrow && this.match(tt.arrow) && !this.canInsertSemicolon()) {
this.next();
return this.parseArrowExpression(
this.startNodeAtNode(id),
[id],
false,
);
}
return id;
}
case tt._do: {
return this.parseDo();
}
case tt.regexp: {
const value = this.state.value;
node = this.parseLiteral(value.value, "RegExpLiteral");
node.pattern = value.pattern;
node.flags = value.flags;
return node;
}
case tt.num:
return this.parseLiteral(this.state.value, "NumericLiteral");
case tt.bigint:
return this.parseLiteral(this.state.value, "BigIntLiteral");
case tt.decimal:
return this.parseLiteral(this.state.value, "DecimalLiteral");
case tt.string:
return this.parseLiteral(this.state.value, "StringLiteral");
case tt._null:
node = this.startNode();
this.next();
return this.finishNode(node, "NullLiteral");
case tt._true:
case tt._false:
return this.parseBooleanLiteral();
case tt.parenL:
return this.parseParenAndDistinguishExpression(canBeArrow);
case tt.bracketBarL:
case tt.bracketHashL: {
return this.parseArrayLike(
this.state.type === tt.bracketBarL ? tt.bracketBarR : tt.bracketR,
/* canBePattern */ false,
/* isTuple */ true,
refExpressionErrors,
);
}
case tt.bracketL: {
return this.parseArrayLike(
tt.bracketR,
/* canBePattern */ true,
/* isTuple */ false,
refExpressionErrors,
);
}
case tt.braceBarL:
case tt.braceHashL: {
return this.parseObjectLike(
this.state.type === tt.braceBarL ? tt.braceBarR : tt.braceR,
/* isPattern */ false,
/* isRecord */ true,
refExpressionErrors,
);
}
case tt.braceL: {
return this.parseObjectLike(
tt.braceR,
/* isPattern */ false,
/* isRecord */ false,
refExpressionErrors,
);
}
case tt._function:
return this.parseFunctionOrFunctionSent();
case tt.at:
this.parseDecorators();
// fall through
case tt._class:
node = this.startNode();
this.takeDecorators(node);
return this.parseClass(node, false);
case tt._new:
return this.parseNewOrNewTarget();
case tt.backQuote:
return this.parseTemplate(false);
// BindExpression[Yield]
// :: MemberExpression[?Yield]
case tt.doubleColon: {
node = this.startNode();
this.next();
node.object = null;
const callee = (node.callee = this.parseNoCallExpr());
if (callee.type === "MemberExpression") {
return this.finishNode(node, "BindExpression");
} else {
throw this.raise(callee.start, Errors.UnsupportedBind);
}
}
case tt.hash: {
if (this.state.inPipeline) {
node = this.startNode();
if (
this.getPluginOption("pipelineOperator", "proposal") !== "smart"
) {
this.raise(node.start, Errors.PrimaryTopicRequiresSmartPipeline);
}
this.next();
if (!this.primaryTopicReferenceIsAllowedInCurrentTopicContext()) {
this.raise(node.start, Errors.PrimaryTopicNotAllowed);
}
this.registerTopicReference();
return this.finishNode(node, "PipelinePrimaryTopicReference");
}
// https://tc39.es/proposal-private-fields-in-in
// RelationalExpression [In, Yield, Await]
// [+In] PrivateIdentifier in ShiftExpression[?Yield, ?Await]
const nextCh = this.input.codePointAt(this.state.end);
if (isIdentifierStart(nextCh) || nextCh === charCodes.backslash) {
const start = this.state.start;
// $FlowIgnore It'll either parse a PrivateName or throw.
node = (this.parseMaybePrivateName(true): N.PrivateName);
if (this.match(tt._in)) {
this.expectPlugin("privateIn");
this.classScope.usePrivateName(node.id.name, node.start);
} else if (this.hasPlugin("privateIn")) {
this.raise(
this.state.start,
Errors.PrivateInExpectedIn,
node.id.name,
);
} else {
throw this.unexpected(start);
}
return node;
}
}
// fall through
case tt.relational: {
if (this.state.value === "<") {
const lookaheadCh = this.input.codePointAt(this.nextTokenStart());
if (
isIdentifierStart(lookaheadCh) || // Element/Type Parameter <foo>
lookaheadCh === charCodes.greaterThan // Fragment <>
) {
this.expectOnePlugin(["jsx", "flow", "typescript"]);
}
}
}
// fall through
default:
throw this.unexpected();
}
}
// async [no LineTerminator here] AsyncArrowBindingIdentifier[?Yield] [no LineTerminator here] => AsyncConciseBody[?In]
parseAsyncArrowUnaryFunction(id: N.Expression): N.ArrowFunctionExpression {
const node = this.startNodeAtNode(id);
// We don't need to push a new ParameterDeclarationScope here since we are sure
// 1) it is an async arrow, 2) no biding pattern is allowed in params
this.prodParam.enter(functionFlags(true, this.prodParam.hasYield));
const params = [this.parseIdentifier()];
this.prodParam.exit();
if (this.hasPrecedingLineBreak()) {
this.raise(this.state.pos, Errors.LineTerminatorBeforeArrow);
}
this.expect(tt.arrow);
// let foo = async bar => {};
this.parseArrowExpression(node, params, true);
return node;
}
// https://github.com/tc39/proposal-do-expressions
parseDo(): N.DoExpression {
this.expectPlugin("doExpressions");
const node = this.startNode();
this.next(); // eat `do`
const oldLabels = this.state.labels;
this.state.labels = [];
node.body = this.parseBlock();
this.state.labels = oldLabels;
return this.finishNode(node, "DoExpression");
}
// Parse the `super` keyword
parseSuper(): N.Super {
const node = this.startNode();
this.next(); // eat `super`
if (
this.match(tt.parenL) &&
!this.scope.allowDirectSuper &&
!this.options.allowSuperOutsideMethod
) {
this.raise(node.start, Errors.SuperNotAllowed);
} else if (
!this.scope.allowSuper &&
!this.options.allowSuperOutsideMethod
) {
this.raise(node.start, Errors.UnexpectedSuper);
}
if (
!this.match(tt.parenL) &&
!this.match(tt.bracketL) &&
!this.match(tt.dot)
) {
this.raise(node.start, Errors.UnsupportedSuper);
}
return this.finishNode(node, "Super");
}
parseBooleanLiteral(): N.BooleanLiteral {
const node = this.startNode();
node.value = this.match(tt._true);
this.next();
return this.finishNode(node, "BooleanLiteral");
}
parseMaybePrivateName(
isPrivateNameAllowed: boolean,
): N.PrivateName | N.Identifier {
const isPrivate = this.match(tt.hash);
if (isPrivate) {
this.expectOnePlugin(["classPrivateProperties", "classPrivateMethods"]);
if (!isPrivateNameAllowed) {
this.raise(this.state.pos, Errors.UnexpectedPrivateField);
}
const node = this.startNode();
this.next();
this.assertNoSpace("Unexpected space between # and identifier");
node.id = this.parseIdentifier(true);
return this.finishNode(node, "PrivateName");
} else {
return this.parseIdentifier(true);
}
}
parseFunctionOrFunctionSent(): N.FunctionExpression | N.MetaProperty {
const node = this.startNode();
// We do not do parseIdentifier here because when parseFunctionOrFunctionSent
// is called we already know that the current token is a "name" with the value "function"
// This will improve perf a tiny little bit as we do not do validation but more importantly
// here is that parseIdentifier will remove an item from the expression stack
// if "function" or "class" is parsed as identifier (in objects e.g.), which should not happen here.
this.next(); // eat `function`
if (this.prodParam.hasYield && this.match(tt.dot)) {
const meta = this.createIdentifier(
this.startNodeAtNode(node),
"function",
);
this.next(); // eat `.`
return this.parseMetaProperty(node, meta, "sent");
}
return this.parseFunction(node);
}
parseMetaProperty(
node: N.MetaProperty,
meta: N.Identifier,
propertyName: string,
): N.MetaProperty {
node.meta = meta;
if (meta.name === "function" && propertyName === "sent") {
// https://github.com/tc39/proposal-function.sent#syntax-1
if (this.isContextual(propertyName)) {
this.expectPlugin("functionSent");
} else if (!this.hasPlugin("functionSent")) {
// The code wasn't `function.sent` but just `function.`, so a simple error is less confusing.
this.unexpected();
}
}
const containsEsc = this.state.containsEsc;
node.property = this.parseIdentifier(true);
if (node.property.name !== propertyName || containsEsc) {
this.raise(
node.property.start,
Errors.UnsupportedMetaProperty,
meta.name,
propertyName,
);
}
return this.finishNode(node, "MetaProperty");
}
// https://tc39.es/ecma262/#prod-ImportMeta
parseImportMetaProperty(node: N.MetaProperty): N.MetaProperty {
const id = this.createIdentifier(this.startNodeAtNode(node), "import");
this.next(); // eat `.`
if (this.isContextual("meta")) {
if (!this.inModule) {
this.raiseWithData(
id.start,
{ code: "BABEL_PARSER_SOURCETYPE_MODULE_REQUIRED" },
Errors.ImportMetaOutsideModule,
);
}
this.sawUnambiguousESM = true;
}
return this.parseMetaProperty(node, id, "meta");
}
parseLiteral<T: N.Literal>(
value: any,
type: /*T["kind"]*/ string,
startPos?: number,
startLoc?: Position,
): T {
startPos = startPos || this.state.start;
startLoc = startLoc || this.state.startLoc;
const node = this.startNodeAt(startPos, startLoc);
this.addExtra(node, "rawValue", value);
this.addExtra(node, "raw", this.input.slice(startPos, this.state.end));
node.value = value;
this.next();
return this.finishNode(node, type);
}
// https://tc39.es/ecma262/#prod-CoverParenthesizedExpressionAndArrowParameterList
parseParenAndDistinguishExpression(canBeArrow: boolean): N.Expression {
const startPos = this.state.start;
const startLoc = this.state.startLoc;
let val;
this.next(); // eat `(`
this.expressionScope.enter(newArrowHeadScope());
const oldMaybeInArrowParameters = this.state.maybeInArrowParameters;
const oldInFSharpPipelineDirectBody = this.state.inFSharpPipelineDirectBody;
this.state.maybeInArrowParameters = true;
this.state.inFSharpPipelineDirectBody = false;
const innerStartPos = this.state.start;
const innerStartLoc = this.state.startLoc;
const exprList = [];
const refExpressionErrors = new ExpressionErrors();
const refNeedsArrowPos = { start: 0 };
let first = true;
let spreadStart;
let optionalCommaStart;
while (!this.match(tt.parenR)) {
if (first) {
first = false;
} else {
this.expect(tt.comma, refNeedsArrowPos.start || null);
if (this.match(tt.parenR)) {
optionalCommaStart = this.state.start;
break;
}
}
if (this.match(tt.ellipsis)) {
const spreadNodeStartPos = this.state.start;
const spreadNodeStartLoc = this.state.startLoc;
spreadStart = this.state.start;
exprList.push(
this.parseParenItem(
this.parseRestBinding(),
spreadNodeStartPos,
spreadNodeStartLoc,
),
);
this.checkCommaAfterRest(charCodes.rightParenthesis);
break;
} else {
exprList.push(
this.parseMaybeAssignAllowIn(
refExpressionErrors,
this.parseParenItem,
refNeedsArrowPos,
),
);
}
}
const innerEndPos = this.state.lastTokEnd;
const innerEndLoc = this.state.lastTokEndLoc;
this.expect(tt.parenR);
this.state.maybeInArrowParameters = oldMaybeInArrowParameters;
this.state.inFSharpPipelineDirectBody = oldInFSharpPipelineDirectBody;
let arrowNode = this.startNodeAt(startPos, startLoc);
if (
canBeArrow &&
this.shouldParseArrow() &&
(arrowNode = this.parseArrow(arrowNode))
) {
this.expressionScope.validateAsPattern();
this.expressionScope.exit();
this.parseArrowExpression(arrowNode, exprList, false);
return arrowNode;
}
this.expressionScope.exit();
if (!exprList.length) {
this.unexpected(this.state.lastTokStart);
}
if (optionalCommaStart) this.unexpected(optionalCommaStart);
if (spreadStart) this.unexpected(spreadStart);
this.checkExpressionErrors(refExpressionErrors, true);
if (refNeedsArrowPos.start) this.unexpected(refNeedsArrowPos.start);
this.toReferencedListDeep(exprList, /* isParenthesizedExpr */ true);
if (exprList.length > 1) {
val = this.startNodeAt(innerStartPos, innerStartLoc);
val.expressions = exprList;
this.finishNodeAt(val, "SequenceExpression", innerEndPos, innerEndLoc);
} else {
val = exprList[0];
}
if (!this.options.createParenthesizedExpressions) {
this.addExtra(val, "parenthesized", true);
this.addExtra(val, "parenStart", startPos);
return val;
}
const parenExpression = this.startNodeAt(startPos, startLoc);
parenExpression.expression = val;
this.finishNode(parenExpression, "ParenthesizedExpression");
return parenExpression;
}
shouldParseArrow(): boolean {
return !this.canInsertSemicolon();
}
parseArrow(node: N.ArrowFunctionExpression): ?N.ArrowFunctionExpression {
if (this.eat(tt.arrow)) {
return node;
}
}
parseParenItem(
node: N.Expression,
startPos: number, // eslint-disable-line no-unused-vars
startLoc: Position, // eslint-disable-line no-unused-vars
): N.Expression {
return node;
}
parseNewOrNewTarget(): N.NewExpression | N.MetaProperty {
const node = this.startNode();
this.next();
if (this.match(tt.dot)) {
// https://tc39.es/ecma262/#prod-NewTarget
const meta = this.createIdentifier(this.startNodeAtNode(node), "new");
this.next();
const metaProp = this.parseMetaProperty(node, meta, "target");
if (!this.scope.inNonArrowFunction && !this.scope.inClass) {
let error = Errors.UnexpectedNewTarget;
if (this.hasPlugin("classProperties")) {
error += " or class properties";
}
/* eslint-disable @babel/development-internal/dry-error-messages */
this.raise(metaProp.start, error);
/* eslint-enable @babel/development-internal/dry-error-messages */
}
return metaProp;
}
return this.parseNew(node);
}
// New's precedence is slightly tricky. It must allow its argument to
// be a `[]` or dot subscript expression, but not a call — at least,
// not without wrapping it in parentheses. Thus, it uses the noCalls
// argument to parseSubscripts to prevent it from consuming the
// argument list.
// https://tc39.es/ecma262/#prod-NewExpression
parseNew(node: N.Expression): N.NewExpression {
node.callee = this.parseNoCallExpr();
if (node.callee.type === "Import") {
this.raise(node.callee.start, Errors.ImportCallNotNewExpression);
} else if (this.isOptionalChain(node.callee)) {
this.raise(this.state.lastTokEnd, Errors.OptionalChainingNoNew);
} else if (this.eat(tt.questionDot)) {
this.raise(this.state.start, Errors.OptionalChainingNoNew);
}
this.parseNewArguments(node);
return this.finishNode(node, "NewExpression");
}
parseNewArguments(node: N.NewExpression): void {
if (this.eat(tt.parenL)) {
const args = this.parseExprList(tt.parenR);
this.toReferencedList(args);
// $FlowFixMe (parseExprList should be all non-null in this case)
node.arguments = args;
} else {
node.arguments = [];
}
}
// Parse template expression.
parseTemplateElement(isTagged: boolean): N.TemplateElement {
const elem = this.startNode();
if (this.state.value === null) {
if (!isTagged) {
this.raise(this.state.start + 1, Errors.InvalidEscapeSequenceTemplate);
}
}
elem.value = {
raw: this.input
.slice(this.state.start, this.state.end)
.replace(/\r\n?/g, "\n"),
cooked: this.state.value,
};
this.next();
elem.tail = this.match(tt.backQuote);
return this.finishNode(elem, "TemplateElement");
}
// https://tc39.es/ecma262/#prod-TemplateLiteral
parseTemplate(isTagged: boolean): N.TemplateLiteral {
const node = this.startNode();
this.next();
node.expressions = [];
let curElt = this.parseTemplateElement(isTagged);
node.quasis = [curElt];
while (!curElt.tail) {
this.expect(tt.dollarBraceL);
node.expressions.push(this.parseTemplateSubstitution());
this.expect(tt.braceR);
node.quasis.push((curElt = this.parseTemplateElement(isTagged)));
}
this.next();
return this.finishNode(node, "TemplateLiteral");
}
// This is overwritten by the TypeScript plugin to parse template types
parseTemplateSubstitution(): N.Expression {
return this.parseExpression();
}
// Parse an object literal, binding pattern, or record.
parseObjectLike<T: N.ObjectPattern | N.ObjectExpression>(
close: TokenType,
isPattern: boolean,
isRecord?: ?boolean,
refExpressionErrors?: ?ExpressionErrors,
): T {
if (isRecord) {
this.expectPlugin("recordAndTuple");
}
const oldInFSharpPipelineDirectBody = this.state.inFSharpPipelineDirectBody;
this.state.inFSharpPipelineDirectBody = false;
const propHash: any = Object.create(null);
let first = true;
const node = this.startNode();
node.properties = [];
this.next();
while (!this.match(close)) {
if (first) {
first = false;
} else {
this.expect(tt.comma);
if (this.match(close)) {
this.addExtra(node, "trailingComma", this.state.lastTokStart);
break;
}
}
const prop = this.parsePropertyDefinition(isPattern, refExpressionErrors);
if (!isPattern) {
// $FlowIgnore RestElement will never be returned if !isPattern
this.checkProto(prop, isRecord, propHash, refExpressionErrors);
}
if (
isRecord &&
!this.isObjectProperty(prop) &&
prop.type !== "SpreadElement"
) {
this.raise(prop.start, Errors.InvalidRecordProperty);
}
// $FlowIgnore
if (prop.shorthand) {
this.addExtra(prop, "shorthand", true);
}
node.properties.push(prop);
}
// The tokenizer uses `braceIsBlock` to detect whether `{` starts a block statement.
// If `{` is a block statement, `exprAllowed` will be `true`.
// However the tokenizer can not handle edge cases like `0 ? a : { a : 1 } / 2`, here
// we update `exprAllowed` when an object-like is parsed.
this.state.exprAllowed = false;
this.next();
this.state.inFSharpPipelineDirectBody = oldInFSharpPipelineDirectBody;
let type = "ObjectExpression";
if (isPattern) {
type = "ObjectPattern";
} else if (isRecord) {
type = "RecordExpression";
}
return this.finishNode(node, type);
}
// Check grammar production:
// IdentifierName *_opt PropertyName
// It is used in `parsePropertyDefinition` to detect AsyncMethod and Accessors
maybeAsyncOrAccessorProp(prop: N.ObjectProperty): boolean {
return (
!prop.computed &&
prop.key.type === "Identifier" &&
(this.isLiteralPropertyName() ||
this.match(tt.bracketL) ||
this.match(tt.star))
);
}
// https://tc39.es/ecma262/#prod-PropertyDefinition
parsePropertyDefinition(
isPattern: boolean,
refExpressionErrors?: ?ExpressionErrors,
): N.ObjectMember | N.SpreadElement | N.RestElement {
let decorators = [];
if (this.match(tt.at)) {
if (this.hasPlugin("decorators")) {
this.raise(this.state.start, Errors.UnsupportedPropertyDecorator);
}
// we needn't check if decorators (stage 0) plugin is enabled since it's checked by
// the call to this.parseDecorator
while (this.match(tt.at)) {
decorators.push(this.parseDecorator());
}
}
const prop = this.startNode();
let isGenerator = false;
let isAsync = false;
let isAccessor = false;
let startPos;
let startLoc;
if (this.match(tt.ellipsis)) {
if (decorators.length) this.unexpected();
if (isPattern) {
this.next();
// Don't use parseRestBinding() as we only allow Identifier here.
prop.argument = this.parseIdentifier();
this.checkCommaAfterRest(charCodes.rightCurlyBrace);
return this.finishNode(prop, "RestElement");
}
return this.parseSpread();
}
if (decorators.length) {
prop.decorators = decorators;
decorators = [];
}
prop.method = false;
if (isPattern || refExpressionErrors) {
startPos = this.state.start;
startLoc = this.state.startLoc;
}
if (!isPattern) {
isGenerator = this.eat(tt.star);
}
const containsEsc = this.state.containsEsc;
const key = this.parsePropertyName(prop, /* isPrivateNameAllowed */ false);
if (
!isPattern &&
!isGenerator &&
!containsEsc &&
this.maybeAsyncOrAccessorProp(prop)
) {
const keyName = key.name;
// https://tc39.es/ecma262/#prod-AsyncMethod
// https://tc39.es/ecma262/#prod-AsyncGeneratorMethod
if (keyName === "async" && !this.hasPrecedingLineBreak()) {
isAsync = true;
isGenerator = this.eat(tt.star);
this.parsePropertyName(prop, /* isPrivateNameAllowed */ false);
}
// get PropertyName[?Yield, ?Await] () { FunctionBody[~Yield, ~Await] }
// set PropertyName[?Yield, ?Await] ( PropertySetParameterList ) { FunctionBody[~Yield, ~Await] }
if (keyName === "get" || keyName === "set") {
isAccessor = true;
prop.kind = keyName;
if (this.match(tt.star)) {
isGenerator = true;
this.raise(this.state.pos, Errors.AccessorIsGenerator, keyName);
this.next();
}
this.parsePropertyName(prop, /* isPrivateNameAllowed */ false);
}
}
this.parseObjPropValue(
prop,
startPos,
startLoc,
isGenerator,
isAsync,
isPattern,
isAccessor,
refExpressionErrors,
);
return prop;
}
getGetterSetterExpectedParamCount(
method: N.ObjectMethod | N.ClassMethod,
): number {
return method.kind === "get" ? 0 : 1;
}
// This exists so we can override within the ESTree plugin
getObjectOrClassMethodParams(method: N.ObjectMethod | N.ClassMethod) {
return method.params;
}
// get methods aren't allowed to have any parameters
// set methods must have exactly 1 parameter which is not a rest parameter
checkGetterSetterParams(method: N.ObjectMethod | N.ClassMethod): void {
const paramCount = this.getGetterSetterExpectedParamCount(method);
const params = this.getObjectOrClassMethodParams(method);
const start = method.start;
if (params.length !== paramCount) {
if (method.kind === "get") {
this.raise(start, Errors.BadGetterArity);
} else {
this.raise(start, Errors.BadSetterArity);
}
}
if (
method.kind === "set" &&
params[params.length - 1]?.type === "RestElement"
) {
this.raise(start, Errors.BadSetterRestParameter);
}
}
// https://tc39.es/ecma262/#prod-MethodDefinition
parseObjectMethod(
prop: N.ObjectMethod,
isGenerator: boolean,
isAsync: boolean,
isPattern: boolean,
isAccessor: boolean,
): ?N.ObjectMethod {
if (isAccessor) {
// isAccessor implies isAsync: false, isPattern: false, isGenerator: false
this.parseMethod(
prop,
// This _should_ be false, but with error recovery, we allow it to be
// set for informational purposes
isGenerator,
/* isAsync */ false,
/* isConstructor */ false,
false,
"ObjectMethod",
);
this.checkGetterSetterParams(prop);
return prop;
}
if (isAsync || isGenerator || this.match(tt.parenL)) {
if (isPattern) this.unexpected();
prop.kind = "method";
prop.method = true;
return this.parseMethod(
prop,
isGenerator,
isAsync,
/* isConstructor */ false,
false,
"ObjectMethod",
);
}
}
// if `isPattern` is true, parse https://tc39.es/ecma262/#prod-BindingProperty
// else https://tc39.es/ecma262/#prod-PropertyDefinition
parseObjectProperty(
prop: N.ObjectProperty,
startPos: ?number,
startLoc: ?Position,
isPattern: boolean,
refExpressionErrors: ?ExpressionErrors,
): ?N.ObjectProperty {
prop.shorthand = false;
if (this.eat(tt.colon)) {
prop.value = isPattern
? this.parseMaybeDefault(this.state.start, this.state.startLoc)
: this.parseMaybeAssignAllowIn(refExpressionErrors);
return this.finishNode(prop, "ObjectProperty");
}
if (!prop.computed && prop.key.type === "Identifier") {
// PropertyDefinition:
// IdentifierReference
// CoveredInitializedName
// Note: `{ eval } = {}` will be checked in `checkLVal` later.
this.checkReservedWord(prop.key.name, prop.key.start, true, false);
if (isPattern) {
prop.value = this.parseMaybeDefault(
startPos,
startLoc,
prop.key.__clone(),
);
} else if (this.match(tt.eq) && refExpressionErrors) {
if (refExpressionErrors.shorthandAssign === -1) {
refExpressionErrors.shorthandAssign = this.state.start;
}
prop.value = this.parseMaybeDefault(
startPos,
startLoc,
prop.key.__clone(),
);
} else {
prop.value = prop.key.__clone();
}
prop.shorthand = true;
return this.finishNode(prop, "ObjectProperty");
}
}
parseObjPropValue(
prop: any,
startPos: ?number,
startLoc: ?Position,
isGenerator: boolean,
isAsync: boolean,
isPattern: boolean,
isAccessor: boolean,
refExpressionErrors?: ?ExpressionErrors,
): void {
const node =
this.parseObjectMethod(
prop,
isGenerator,
isAsync,
isPattern,
isAccessor,
) ||
this.parseObjectProperty(
prop,
startPos,
startLoc,
isPattern,
refExpressionErrors,
);
if (!node) this.unexpected();
// $FlowFixMe
return node;
}
parsePropertyName(
prop: N.ObjectOrClassMember | N.ClassMember | N.TsNamedTypeElementBase,
isPrivateNameAllowed: boolean,
): N.Expression | N.Identifier {
if (this.eat(tt.bracketL)) {
(prop: $FlowSubtype<N.ObjectOrClassMember>).computed = true;
prop.key = this.parseMaybeAssignAllowIn();
this.expect(tt.bracketR);
} else {
const oldInPropertyName = this.state.inPropertyName;
this.state.inPropertyName = true;
// We check if it's valid for it to be a private name when we push it.
(prop: $FlowFixMe).key =
this.match(tt.num) ||
this.match(tt.string) ||
this.match(tt.bigint) ||
this.match(tt.decimal)
? this.parseExprAtom()
: this.parseMaybePrivateName(isPrivateNameAllowed);
if (!this.isPrivateName(prop.key)) {
// ClassPrivateProperty is never computed, so we don't assign in that case.
prop.computed = false;
}
this.state.inPropertyName = oldInPropertyName;
}
return prop.key;
}
// Initialize empty function node.
initFunction(node: N.BodilessFunctionOrMethodBase, isAsync: ?boolean): void {
node.id = null;
node.generator = false;
node.async = !!isAsync;
}
// Parse object or class method.
parseMethod<T: N.MethodLike>(
node: T,
isGenerator: boolean,
isAsync: boolean,
isConstructor: boolean,
allowDirectSuper: boolean,
type: string,
inClassScope: boolean = false,
): T {
this.initFunction(node, isAsync);
node.generator = !!isGenerator;
const allowModifiers = isConstructor; // For TypeScript parameter properties
this.scope.enter(
SCOPE_FUNCTION |
SCOPE_SUPER |
(inClassScope ? SCOPE_CLASS : 0) |
(allowDirectSuper ? SCOPE_DIRECT_SUPER : 0),
);
this.prodParam.enter(functionFlags(isAsync, node.generator));
this.parseFunctionParams((node: any), allowModifiers);
this.parseFunctionBodyAndFinish(node, type, true);
this.prodParam.exit();
this.scope.exit();
return node;
}
// parse an array literal or tuple literal
// https://tc39.es/ecma262/#prod-ArrayLiteral
// https://tc39.es/proposal-record-tuple/#prod-TupleLiteral
parseArrayLike(
close: TokenType,
canBePattern: boolean,
isTuple: boolean,
refExpressionErrors: ?ExpressionErrors,
): N.ArrayExpression | N.TupleExpression {
if (isTuple) {
this.expectPlugin("recordAndTuple");
}
const oldInFSharpPipelineDirectBody = this.state.inFSharpPipelineDirectBody;
this.state.inFSharpPipelineDirectBody = false;
const node = this.startNode();
this.next();
node.elements = this.parseExprList(
close,
/* allowEmpty */ !isTuple,
refExpressionErrors,
node,
);
this.state.inFSharpPipelineDirectBody = oldInFSharpPipelineDirectBody;
return this.finishNode(
node,
isTuple ? "TupleExpression" : "ArrayExpression",
);
}
// Parse arrow function expression.
// If the parameters are provided, they will be converted to an
// assignable list.
parseArrowExpression(
node: N.ArrowFunctionExpression,
params: ?(N.Expression[]),
isAsync: boolean,
trailingCommaPos: ?number,
): N.ArrowFunctionExpression {
this.scope.enter(SCOPE_FUNCTION | SCOPE_ARROW);
let flags = functionFlags(isAsync, false);
// ConciseBody and AsyncConciseBody inherit [In]
if (!this.match(tt.bracketL) && this.prodParam.hasIn) {
flags |= PARAM_IN;
}
this.prodParam.enter(flags);
this.initFunction(node, isAsync);
const oldMaybeInArrowParameters = this.state.maybeInArrowParameters;
if (params) {
this.state.maybeInArrowParameters = true;
this.setArrowFunctionParameters(node, params, trailingCommaPos);
}
this.state.maybeInArrowParameters = false;
this.parseFunctionBody(node, true);
this.prodParam.exit();
this.scope.exit();
this.state.maybeInArrowParameters = oldMaybeInArrowParameters;
return this.finishNode(node, "ArrowFunctionExpression");
}
setArrowFunctionParameters(
node: N.ArrowFunctionExpression,
params: N.Expression[],
trailingCommaPos: ?number,
): void {
node.params = this.toAssignableList(params, trailingCommaPos, false);
}
parseFunctionBodyAndFinish(
node: N.BodilessFunctionOrMethodBase,
type: string,
isMethod?: boolean = false,
): void {
// $FlowIgnore (node is not bodiless if we get here)
this.parseFunctionBody(node, false, isMethod);
this.finishNode(node, type);
}
// Parse function body and check parameters.
parseFunctionBody(
node: N.Function,
allowExpression: ?boolean,
isMethod?: boolean = false,
): void {
const isExpression = allowExpression && !this.match(tt.braceL);
this.expressionScope.enter(newExpressionScope());
if (isExpression) {
// https://tc39.es/ecma262/#prod-ExpressionBody
node.body = this.parseMaybeAssign();
this.checkParams(node, false, allowExpression, false);
} else {
const oldStrict = this.state.strict;
// Start a new scope with regard to labels
// flag (restore them to their old value afterwards).
const oldLabels = this.state.labels;
this.state.labels = [];
// FunctionBody[Yield, Await]:
// StatementList[?Yield, ?Await, +Return] opt
this.prodParam.enter(this.prodParam.currentFlags() | PARAM_RETURN);
node.body = this.parseBlock(
true,
false,
// Strict mode function checks after we parse the statements in the function body.
(hasStrictModeDirective: boolean) => {
const nonSimple = !this.isSimpleParamList(node.params);
if (hasStrictModeDirective && nonSimple) {
// This logic is here to align the error location with the ESTree plugin.
const errorPos =
// $FlowIgnore
(node.kind === "method" || node.kind === "constructor") &&
// $FlowIgnore
!!node.key
? node.key.end
: node.start;
this.raise(errorPos, Errors.IllegalLanguageModeDirective);
}
const strictModeChanged = !oldStrict && this.state.strict;
// Add the params to varDeclaredNames to ensure that an error is thrown
// if a let/const declaration in the function clashes with one of the params.
this.checkParams(
node,
!this.state.strict && !allowExpression && !isMethod && !nonSimple,
allowExpression,
strictModeChanged,
);
// Ensure the function name isn't a forbidden identifier in strict mode, e.g. 'eval'
if (this.state.strict && node.id) {
this.checkLVal(
node.id,
"function name",
BIND_OUTSIDE,
undefined,
undefined,
strictModeChanged,
);
}
},
);
this.prodParam.exit();
this.expressionScope.exit();
this.state.labels = oldLabels;
}
}
isSimpleParamList(
params: $ReadOnlyArray<N.Pattern | N.TSParameterProperty>,
): boolean {
for (let i = 0, len = params.length; i < len; i++) {
if (params[i].type !== "Identifier") return false;
}
return true;
}
checkParams(
node: N.Function,
allowDuplicates: boolean,
// eslint-disable-next-line no-unused-vars
isArrowFunction: ?boolean,
strictModeChanged?: boolean = true,
): void {
const checkClashes = new Set();
for (const param of node.params) {
this.checkLVal(
param,
"function parameter list",
BIND_VAR,
allowDuplicates ? null : checkClashes,
undefined,
strictModeChanged,
);
}
}
// Parses a comma-separated list of expressions, and returns them as
// an array. `close` is the token type that ends the list, and
// `allowEmpty` can be turned on to allow subsequent commas with
// nothing in between them to be parsed as `null` (which is needed
// for array literals).
parseExprList(
close: TokenType,
allowEmpty?: boolean,
refExpressionErrors?: ?ExpressionErrors,
nodeForExtra?: ?N.Node,
): $ReadOnlyArray<?N.Expression> {
const elts = [];
let first = true;
while (!this.eat(close)) {
if (first) {
first = false;
} else {
this.expect(tt.comma);
if (this.match(close)) {
if (nodeForExtra) {
this.addExtra(
nodeForExtra,
"trailingComma",
this.state.lastTokStart,
);
}
this.next();
break;
}
}
elts.push(this.parseExprListItem(allowEmpty, refExpressionErrors));
}
return elts;
}
parseExprListItem(
allowEmpty: ?boolean,
refExpressionErrors?: ?ExpressionErrors,
refNeedsArrowPos: ?Pos,
allowPlaceholder: ?boolean,
): ?N.Expression {
let elt;
if (this.match(tt.comma)) {
if (!allowEmpty) {
this.raise(this.state.pos, Errors.UnexpectedToken, ",");
}
elt = null;
} else if (this.match(tt.ellipsis)) {
const spreadNodeStartPos = this.state.start;
const spreadNodeStartLoc = this.state.startLoc;
elt = this.parseParenItem(
this.parseSpread(refExpressionErrors, refNeedsArrowPos),
spreadNodeStartPos,
spreadNodeStartLoc,
);
} else if (this.match(tt.question)) {
this.expectPlugin("partialApplication");
if (!allowPlaceholder) {
this.raise(this.state.start, Errors.UnexpectedArgumentPlaceholder);
}
const node = this.startNode();
this.next();
elt = this.finishNode(node, "ArgumentPlaceholder");
} else {
elt = this.parseMaybeAssignAllowIn(
refExpressionErrors,
this.parseParenItem,
refNeedsArrowPos,
);
}
return elt;
}
// Parse the next token as an identifier. If `liberal` is true (used
// when parsing properties), it will also convert keywords into
// identifiers.
// This shouldn't be used to parse the keywords of meta properties, since they
// are not identifiers and cannot contain escape sequences.
parseIdentifier(liberal?: boolean): N.Identifier {
const node = this.startNode();
const name = this.parseIdentifierName(node.start, liberal);
return this.createIdentifier(node, name);
}
createIdentifier(node: N.Identifier, name: string): N.Identifier {
node.name = name;
node.loc.identifierName = name;
return this.finishNode(node, "Identifier");
}
parseIdentifierName(pos: number, liberal?: boolean): string {
let name: string;
const { start, type } = this.state;
if (type === tt.name) {
name = this.state.value;
} else if (type.keyword) {
name = type.keyword;
// `class` and `function` keywords push function-type token context into this.context.
// But there is no chance to pop the context if the keyword is consumed
// as an identifier such as a property name.
const curContext = this.curContext();
if (
(type === tt._class || type === tt._function) &&
(curContext === ct.functionStatement ||
curContext === ct.functionExpression)
) {
this.state.context.pop();
}
} else {
throw this.unexpected();
}
if (liberal) {
// If the current token is not used as a keyword, set its type to "tt.name".
// This will prevent this.next() from throwing about unexpected escapes.
this.state.type = tt.name;
} else {
this.checkReservedWord(name, start, !!type.keyword, false);
}
this.next();
return name;
}
checkReservedWord(
word: string,
startLoc: number,
checkKeywords: boolean,
isBinding: boolean,
): void {
if (this.prodParam.hasYield && word === "yield") {
this.raise(startLoc, Errors.YieldBindingIdentifier);
return;
}
if (word === "await") {
if (this.prodParam.hasAwait) {
this.raise(startLoc, Errors.AwaitBindingIdentifier);
return;
} else {
this.expressionScope.recordAsyncArrowParametersError(
startLoc,
Errors.AwaitBindingIdentifier,
);
}
}
if (
this.scope.inClass &&
!this.scope.inNonArrowFunction &&
word === "arguments"
) {
this.raise(startLoc, Errors.ArgumentsInClass);
return;
}
if (checkKeywords && isKeyword(word)) {
this.raise(startLoc, Errors.UnexpectedKeyword, word);
return;
}
const reservedTest = !this.state.strict
? isReservedWord
: isBinding
? isStrictBindReservedWord
: isStrictReservedWord;
if (reservedTest(word, this.inModule)) {
if (!this.prodParam.hasAwait && word === "await") {
this.raise(
startLoc,
this.hasPlugin("topLevelAwait")
? Errors.AwaitNotInAsyncContext
: Errors.AwaitNotInAsyncFunction,
);
} else {
this.raise(startLoc, Errors.UnexpectedReservedWord, word);
}
}
}
isAwaitAllowed(): boolean {
if (this.prodParam.hasAwait) return true;
if (this.options.allowAwaitOutsideFunction && !this.scope.inFunction) {
return true;
}
return false;
}
// Parses await expression inside async function.
parseAwait(): N.AwaitExpression {
const node = this.startNode();
this.next();
this.expressionScope.recordParameterInitializerError(
node.start,
Errors.AwaitExpressionFormalParameter,
);
if (this.eat(tt.star)) {
this.raise(node.start, Errors.ObsoleteAwaitStar);
}
if (!this.scope.inFunction && !this.options.allowAwaitOutsideFunction) {
if (
this.hasPrecedingLineBreak() ||
// All the following expressions are ambiguous:
// await + 0, await - 0, await ( 0 ), await [ 0 ], await / 0 /u, await ``
this.match(tt.plusMin) ||
this.match(tt.parenL) ||
this.match(tt.bracketL) ||
this.match(tt.backQuote) ||
// Sometimes the tokenizer generates tt.slash for regexps, and this is
// handler by parseExprAtom
this.match(tt.regexp) ||
this.match(tt.slash) ||
// This code could be parsed both as a modulo operator or as an intrinsic:
// await %x(0)
(this.hasPlugin("v8intrinsic") && this.match(tt.modulo))
) {
this.ambiguousScriptDifferentAst = true;
} else {
this.sawUnambiguousESM = true;
}
}
if (!this.state.soloAwait) {
node.argument = this.parseMaybeUnary();
}
return this.finishNode(node, "AwaitExpression");
}
// Parses yield expression inside generator.
parseYield(): N.YieldExpression {
const node = this.startNode();
this.expressionScope.recordParameterInitializerError(
node.start,
Errors.YieldInParameter,
);
this.next();
if (
this.match(tt.semi) ||
(!this.match(tt.star) && !this.state.type.startsExpr) ||
this.hasPrecedingLineBreak()
) {
node.delegate = false;
node.argument = null;
} else {
node.delegate = this.eat(tt.star);
node.argument = this.parseMaybeAssign();
}
return this.finishNode(node, "YieldExpression");
}
// Validates a pipeline (for any of the pipeline Babylon plugins) at the point
// of the infix operator `|>`.
checkPipelineAtInfixOperator(left: N.Expression, leftStartPos: number) {
if (this.getPluginOption("pipelineOperator", "proposal") === "smart") {
if (left.type === "SequenceExpression") {
// Ensure that the pipeline head is not a comma-delimited
// sequence expression.
this.raise(leftStartPos, Errors.PipelineHeadSequenceExpression);
}
}
}
parseSmartPipelineBody(
childExpression: N.Expression,
startPos: number,
startLoc: Position,
): N.PipelineBody {
this.checkSmartPipelineBodyEarlyErrors(childExpression, startPos);
return this.parseSmartPipelineBodyInStyle(
childExpression,
startPos,
startLoc,
);
}
checkSmartPipelineBodyEarlyErrors(
childExpression: N.Expression,
startPos: number,
): void {
if (this.match(tt.arrow)) {
// If the following token is invalidly `=>`, then throw a human-friendly error
// instead of something like 'Unexpected token, expected ";"'.
throw this.raise(this.state.start, Errors.PipelineBodyNoArrow);
} else if (childExpression.type === "SequenceExpression") {
this.raise(startPos, Errors.PipelineBodySequenceExpression);
}
}
parseSmartPipelineBodyInStyle(
childExpression: N.Expression,
startPos: number,
startLoc: Position,
): N.PipelineBody {
const bodyNode = this.startNodeAt(startPos, startLoc);
const isSimpleReference = this.isSimpleReference(childExpression);
if (isSimpleReference) {
bodyNode.callee = childExpression;
} else {
if (!this.topicReferenceWasUsedInCurrentTopicContext()) {
this.raise(startPos, Errors.PipelineTopicUnused);
}
bodyNode.expression = childExpression;
}
return this.finishNode(
bodyNode,
isSimpleReference ? "PipelineBareFunction" : "PipelineTopicExpression",
);
}
isSimpleReference(expression: N.Expression): boolean {
switch (expression.type) {
case "MemberExpression":
return (
!expression.computed && this.isSimpleReference(expression.object)
);
case "Identifier":
return true;
default:
return false;
}
}
// Enable topic references from outer contexts within smart pipeline bodies.
// The function modifies the parser's topic-context state to enable or disable
// the use of topic references with the smartPipelines plugin. They then run a
// callback, then they reset the parser to the old topic-context state that it
// had before the function was called.
withTopicPermittingContext<T>(callback: () => T): T {
const outerContextTopicState = this.state.topicContext;
this.state.topicContext = {
// Enable the use of the primary topic reference.
maxNumOfResolvableTopics: 1,
// Hide the use of any topic references from outer contexts.
maxTopicIndex: null,
};
try {
return callback();
} finally {
this.state.topicContext = outerContextTopicState;
}
}
// Disable topic references from outer contexts within syntax constructs
// such as the bodies of iteration statements.
// The function modifies the parser's topic-context state to enable or disable
// the use of topic references with the smartPipelines plugin. They then run a
// callback, then they reset the parser to the old topic-context state that it
// had before the function was called.
withTopicForbiddingContext<T>(callback: () => T): T {
const outerContextTopicState = this.state.topicContext;
this.state.topicContext = {
// Disable the use of the primary topic reference.
maxNumOfResolvableTopics: 0,
// Hide the use of any topic references from outer contexts.
maxTopicIndex: null,
};
try {
return callback();
} finally {
this.state.topicContext = outerContextTopicState;
}
}
withSoloAwaitPermittingContext<T>(callback: () => T): T {
const outerContextSoloAwaitState = this.state.soloAwait;
this.state.soloAwait = true;
try {
return callback();
} finally {
this.state.soloAwait = outerContextSoloAwaitState;
}
}
allowInAnd<T>(callback: () => T): T {
const flags = this.prodParam.currentFlags();
const prodParamToSet = PARAM_IN & ~flags;
if (prodParamToSet) {
this.prodParam.enter(flags | PARAM_IN);
try {
return callback();
} finally {
this.prodParam.exit();
}
}
return callback();
}
disallowInAnd<T>(callback: () => T): T {
const flags = this.prodParam.currentFlags();
const prodParamToClear = PARAM_IN & flags;
if (prodParamToClear) {
this.prodParam.enter(flags & ~PARAM_IN);
try {
return callback();
} finally {
this.prodParam.exit();
}
}
return callback();
}
// Register the use of a primary topic reference (`#`) within the current
// topic context.
registerTopicReference(): void {
this.state.topicContext.maxTopicIndex = 0;
}
primaryTopicReferenceIsAllowedInCurrentTopicContext(): boolean {
return this.state.topicContext.maxNumOfResolvableTopics >= 1;
}
topicReferenceWasUsedInCurrentTopicContext(): boolean {
return (
this.state.topicContext.maxTopicIndex != null &&
this.state.topicContext.maxTopicIndex >= 0
);
}
parseFSharpPipelineBody(prec: number): N.Expression {
const startPos = this.state.start;
const startLoc = this.state.startLoc;
this.state.potentialArrowAt = this.state.start;
const oldInFSharpPipelineDirectBody = this.state.inFSharpPipelineDirectBody;
this.state.inFSharpPipelineDirectBody = true;
const ret = this.parseExprOp(
this.parseMaybeUnary(),
startPos,
startLoc,
prec,
);
this.state.inFSharpPipelineDirectBody = oldInFSharpPipelineDirectBody;
return ret;
}
}