babel/src/tokenizer/index.js
Karl Cheng 65bea96544 Add support for class private methods (#703)
* Add support for class private methods

This commit adds parser support for the TC39 Stage 2 Private Methods
proposal.

This commit also changes "key" in ClassPrivateProperty from an
Identifier to a PrivateName, as well as disallowing #constructor as a
valid private field name.

* Add tests for string literal get/set/async

These should be treated as regular methods and not special get/set/async
behaviour.

* Add tests for class private methods

This also removes a test from the Test262 whitelist that failed before
the changes for private methods support and now passes.

* Modify class private prop tests for PrivateName

* Add class private prop tests for #constructor

* Fix existing ASI test case failure
2017-09-06 18:09:12 -04:00

1171 lines
32 KiB
JavaScript

/* eslint max-len: 0 */
// @flow
import type { Options } from "../options";
import type { Position } from "../util/location";
import {
isIdentifierStart,
isIdentifierChar,
isKeyword,
} from "../util/identifier";
import { types as tt, keywords as keywordTypes, type TokenType } from "./types";
import { type TokContext, types as ct } from "./context";
import LocationParser from "../parser/location";
import { SourceLocation } from "../util/location";
import {
lineBreak,
lineBreakG,
isNewLine,
nonASCIIwhitespace,
} from "../util/whitespace";
import State from "./state";
// The following character codes are forbidden from being
// an immediate sibling of NumericLiteralSeparator _
const forbiddenNumericSeparatorSiblings = {
decBinOct: [
46, // .
66, // B
69, // E
79, // O
95, // _ (multiple separators are not allowed)
98, // b
101, // e
111, // o
],
hex: [
46, // .
88, // X
95, // _ (multiple separators are not allowed)
120, // x
],
};
// Object type used to represent tokens. Note that normally, tokens
// simply exist as properties on the parser object. This is only
// used for the onToken callback and the external tokenizer.
export class Token {
constructor(state: State) {
this.type = state.type;
this.value = state.value;
this.start = state.start;
this.end = state.end;
this.loc = new SourceLocation(state.startLoc, state.endLoc);
}
type: TokenType;
value: any;
start: number;
end: number;
loc: SourceLocation;
}
// ## Tokenizer
function codePointToString(code: number): string {
// UTF-16 Decoding
if (code <= 0xffff) {
return String.fromCharCode(code);
} else {
return String.fromCharCode(
((code - 0x10000) >> 10) + 0xd800,
((code - 0x10000) & 1023) + 0xdc00,
);
}
}
export default class Tokenizer extends LocationParser {
// Forward-declarations
// parser/util.js
+unexpected: (pos?: ?number, messageOrType?: string | TokenType) => empty;
isLookahead: boolean;
constructor(options: Options, input: string) {
super();
this.state = new State();
this.state.init(options, input);
this.isLookahead = false;
}
// Move to the next token
next(): void {
if (this.options.tokens && !this.isLookahead) {
this.state.tokens.push(new Token(this.state));
}
this.state.lastTokEnd = this.state.end;
this.state.lastTokStart = this.state.start;
this.state.lastTokEndLoc = this.state.endLoc;
this.state.lastTokStartLoc = this.state.startLoc;
this.nextToken();
}
// TODO
eat(type: TokenType): boolean {
if (this.match(type)) {
this.next();
return true;
} else {
return false;
}
}
// TODO
match(type: TokenType): boolean {
return this.state.type === type;
}
// TODO
isKeyword(word: string): boolean {
return isKeyword(word);
}
// TODO
lookahead(): State {
const old = this.state;
this.state = old.clone(true);
this.isLookahead = true;
this.next();
this.isLookahead = false;
const curr = this.state;
this.state = old;
return curr;
}
// Toggle strict mode. Re-reads the next number or string to please
// pedantic tests (`"use strict"; 010;` should fail).
setStrict(strict: boolean): void {
this.state.strict = strict;
if (!this.match(tt.num) && !this.match(tt.string)) return;
this.state.pos = this.state.start;
while (this.state.pos < this.state.lineStart) {
this.state.lineStart =
this.input.lastIndexOf("\n", this.state.lineStart - 2) + 1;
--this.state.curLine;
}
this.nextToken();
}
curContext(): TokContext {
return this.state.context[this.state.context.length - 1];
}
// Read a single token, updating the parser object's token-related
// properties.
nextToken(): void {
const curContext = this.curContext();
if (!curContext || !curContext.preserveSpace) this.skipSpace();
this.state.containsOctal = false;
this.state.octalPosition = null;
this.state.start = this.state.pos;
this.state.startLoc = this.state.curPosition();
if (this.state.pos >= this.input.length) return this.finishToken(tt.eof);
if (curContext.override) {
return curContext.override(this);
} else {
return this.readToken(this.fullCharCodeAtPos());
}
}
readToken(code: number): void {
// Identifier or keyword. '\uXXXX' sequences are allowed in
// identifiers, so '\' also dispatches to that.
if (isIdentifierStart(code) || code === 92 /* '\' */) {
return this.readWord();
} else {
return this.getTokenFromCode(code);
}
}
fullCharCodeAtPos(): number {
const code = this.input.charCodeAt(this.state.pos);
if (code <= 0xd7ff || code >= 0xe000) return code;
const next = this.input.charCodeAt(this.state.pos + 1);
return (code << 10) + next - 0x35fdc00;
}
pushComment(
block: boolean,
text: string,
start: number,
end: number,
startLoc: Position,
endLoc: Position,
): void {
const comment = {
type: block ? "CommentBlock" : "CommentLine",
value: text,
start: start,
end: end,
loc: new SourceLocation(startLoc, endLoc),
};
if (!this.isLookahead) {
if (this.options.tokens) this.state.tokens.push(comment);
this.state.comments.push(comment);
this.addComment(comment);
}
}
skipBlockComment(): void {
const startLoc = this.state.curPosition();
const start = this.state.pos;
const end = this.input.indexOf("*/", (this.state.pos += 2));
if (end === -1) this.raise(this.state.pos - 2, "Unterminated comment");
this.state.pos = end + 2;
lineBreakG.lastIndex = start;
let match;
while (
(match = lineBreakG.exec(this.input)) &&
match.index < this.state.pos
) {
++this.state.curLine;
this.state.lineStart = match.index + match[0].length;
}
this.pushComment(
true,
this.input.slice(start + 2, end),
start,
this.state.pos,
startLoc,
this.state.curPosition(),
);
}
skipLineComment(startSkip: number): void {
const start = this.state.pos;
const startLoc = this.state.curPosition();
let ch = this.input.charCodeAt((this.state.pos += startSkip));
if (this.state.pos < this.input.length) {
while (
ch !== 10 &&
ch !== 13 &&
ch !== 8232 &&
ch !== 8233 &&
++this.state.pos < this.input.length
) {
ch = this.input.charCodeAt(this.state.pos);
}
}
this.pushComment(
false,
this.input.slice(start + startSkip, this.state.pos),
start,
this.state.pos,
startLoc,
this.state.curPosition(),
);
}
// Called at the start of the parse and after every token. Skips
// whitespace and comments, and.
skipSpace(): void {
loop: while (this.state.pos < this.input.length) {
const ch = this.input.charCodeAt(this.state.pos);
switch (ch) {
case 32: // space
case 160: // non-breaking space
++this.state.pos;
break;
case 13: // '\r' carriage return
if (this.input.charCodeAt(this.state.pos + 1) === 10) {
++this.state.pos;
}
case 10: // '\n' line feed
case 8232: // line separator
case 8233: // paragraph separator
++this.state.pos;
++this.state.curLine;
this.state.lineStart = this.state.pos;
break;
case 47: // '/'
switch (this.input.charCodeAt(this.state.pos + 1)) {
case 42: // '*'
this.skipBlockComment();
break;
case 47:
this.skipLineComment(2);
break;
default:
break loop;
}
break;
default:
if (
(ch > 8 && ch < 14) ||
(ch >= 5760 && nonASCIIwhitespace.test(String.fromCharCode(ch)))
) {
++this.state.pos;
} else {
break loop;
}
}
}
}
// Called at the end of every token. Sets `end`, `val`, and
// maintains `context` and `exprAllowed`, and skips the space after
// the token, so that the next one's `start` will point at the
// right position.
finishToken(type: TokenType, val: any): void {
this.state.end = this.state.pos;
this.state.endLoc = this.state.curPosition();
const prevType = this.state.type;
this.state.type = type;
this.state.value = val;
this.updateContext(prevType);
}
// ### Token reading
// This is the function that is called to fetch the next token. It
// is somewhat obscure, because it works in character codes rather
// than characters, and because operator parsing has been inlined
// into it.
//
// All in the name of speed.
//
readToken_dot(): void {
const next = this.input.charCodeAt(this.state.pos + 1);
if (next >= 48 && next <= 57) {
return this.readNumber(true);
}
const next2 = this.input.charCodeAt(this.state.pos + 2);
if (next === 46 && next2 === 46) {
// 46 = dot '.'
this.state.pos += 3;
return this.finishToken(tt.ellipsis);
} else {
++this.state.pos;
return this.finishToken(tt.dot);
}
}
readToken_slash(): void {
// '/'
if (this.state.exprAllowed) {
++this.state.pos;
return this.readRegexp();
}
const next = this.input.charCodeAt(this.state.pos + 1);
if (next === 61) {
return this.finishOp(tt.assign, 2);
} else {
return this.finishOp(tt.slash, 1);
}
}
readToken_mult_modulo(code: number): void {
// '%*'
let type = code === 42 ? tt.star : tt.modulo;
let width = 1;
let next = this.input.charCodeAt(this.state.pos + 1);
// Exponentiation operator **
if (code === 42 && next === 42) {
width++;
next = this.input.charCodeAt(this.state.pos + 2);
type = tt.exponent;
}
if (next === 61) {
width++;
type = tt.assign;
}
return this.finishOp(type, width);
}
readToken_pipe_amp(code: number): void {
// '|&'
const next = this.input.charCodeAt(this.state.pos + 1);
if (next === code)
return this.finishOp(code === 124 ? tt.logicalOR : tt.logicalAND, 2);
if (next === 61) return this.finishOp(tt.assign, 2);
if (code === 124 && next === 125 && this.hasPlugin("flow"))
return this.finishOp(tt.braceBarR, 2);
return this.finishOp(code === 124 ? tt.bitwiseOR : tt.bitwiseAND, 1);
}
readToken_caret(): void {
// '^'
const next = this.input.charCodeAt(this.state.pos + 1);
if (next === 61) {
return this.finishOp(tt.assign, 2);
} else {
return this.finishOp(tt.bitwiseXOR, 1);
}
}
readToken_plus_min(code: number): void {
// '+-'
const next = this.input.charCodeAt(this.state.pos + 1);
if (next === code) {
if (
next === 45 &&
!this.inModule &&
this.input.charCodeAt(this.state.pos + 2) === 62 &&
lineBreak.test(this.input.slice(this.state.lastTokEnd, this.state.pos))
) {
// A `-->` line comment
this.skipLineComment(3);
this.skipSpace();
return this.nextToken();
}
return this.finishOp(tt.incDec, 2);
}
if (next === 61) {
return this.finishOp(tt.assign, 2);
} else {
return this.finishOp(tt.plusMin, 1);
}
}
readToken_lt_gt(code: number): void {
// '<>'
const next = this.input.charCodeAt(this.state.pos + 1);
let size = 1;
if (next === code) {
size =
code === 62 && this.input.charCodeAt(this.state.pos + 2) === 62 ? 3 : 2;
if (this.input.charCodeAt(this.state.pos + size) === 61)
return this.finishOp(tt.assign, size + 1);
return this.finishOp(tt.bitShift, size);
}
if (
next === 33 &&
code === 60 &&
!this.inModule &&
this.input.charCodeAt(this.state.pos + 2) === 45 &&
this.input.charCodeAt(this.state.pos + 3) === 45
) {
// `<!--`, an XML-style comment that should be interpreted as a line comment
this.skipLineComment(4);
this.skipSpace();
return this.nextToken();
}
if (next === 61) {
// <= | >=
size = 2;
}
return this.finishOp(tt.relational, size);
}
readToken_eq_excl(code: number): void {
// '=!'
const next = this.input.charCodeAt(this.state.pos + 1);
if (next === 61)
return this.finishOp(
tt.equality,
this.input.charCodeAt(this.state.pos + 2) === 61 ? 3 : 2,
);
if (code === 61 && next === 62) {
// '=>'
this.state.pos += 2;
return this.finishToken(tt.arrow);
}
return this.finishOp(code === 61 ? tt.eq : tt.bang, 1);
}
readToken_question() {
// '?'
const next = this.input.charCodeAt(this.state.pos + 1);
const next2 = this.input.charCodeAt(this.state.pos + 2);
if (next === 46 && !(next2 >= 48 && next2 <= 57)) {
// '.' not followed by a number
this.state.pos += 2;
return this.finishToken(tt.questionDot);
} else {
++this.state.pos;
return this.finishToken(tt.question);
}
}
getTokenFromCode(code: number): void {
switch (code) {
case 35: // '#'
if (
(this.hasPlugin("classPrivateProperties") ||
this.hasPlugin("classPrivateMethods")) &&
this.state.classLevel > 0
) {
++this.state.pos;
return this.finishToken(tt.hash);
} else {
this.raise(
this.state.pos,
`Unexpected character '${codePointToString(code)}'`,
);
}
// The interpretation of a dot depends on whether it is followed
// by a digit or another two dots.
case 46: // '.'
return this.readToken_dot();
// Punctuation tokens.
case 40:
++this.state.pos;
return this.finishToken(tt.parenL);
case 41:
++this.state.pos;
return this.finishToken(tt.parenR);
case 59:
++this.state.pos;
return this.finishToken(tt.semi);
case 44:
++this.state.pos;
return this.finishToken(tt.comma);
case 91:
++this.state.pos;
return this.finishToken(tt.bracketL);
case 93:
++this.state.pos;
return this.finishToken(tt.bracketR);
case 123:
if (
this.hasPlugin("flow") &&
this.input.charCodeAt(this.state.pos + 1) === 124
) {
return this.finishOp(tt.braceBarL, 2);
} else {
++this.state.pos;
return this.finishToken(tt.braceL);
}
case 125:
++this.state.pos;
return this.finishToken(tt.braceR);
case 58:
if (
this.hasPlugin("functionBind") &&
this.input.charCodeAt(this.state.pos + 1) === 58
) {
return this.finishOp(tt.doubleColon, 2);
} else {
++this.state.pos;
return this.finishToken(tt.colon);
}
case 63:
return this.readToken_question();
case 64:
++this.state.pos;
return this.finishToken(tt.at);
case 96: // '`'
++this.state.pos;
return this.finishToken(tt.backQuote);
case 48: {
// '0'
const next = this.input.charCodeAt(this.state.pos + 1);
if (next === 120 || next === 88) return this.readRadixNumber(16); // '0x', '0X' - hex number
if (next === 111 || next === 79) return this.readRadixNumber(8); // '0o', '0O' - octal number
if (next === 98 || next === 66) return this.readRadixNumber(2); // '0b', '0B' - binary number
}
// Anything else beginning with a digit is an integer, octal
// number, or float.
case 49:
case 50:
case 51:
case 52:
case 53:
case 54:
case 55:
case 56:
case 57: // 1-9
return this.readNumber(false);
// Quotes produce strings.
case 34:
case 39: // '"', "'"
return this.readString(code);
// Operators are parsed inline in tiny state machines. '=' (61) is
// often referred to. `finishOp` simply skips the amount of
// characters it is given as second argument, and returns a token
// of the type given by its first argument.
case 47: // '/'
return this.readToken_slash();
case 37:
case 42: // '%*'
return this.readToken_mult_modulo(code);
case 124:
case 38: // '|&'
return this.readToken_pipe_amp(code);
case 94: // '^'
return this.readToken_caret();
case 43:
case 45: // '+-'
return this.readToken_plus_min(code);
case 60:
case 62: // '<>'
return this.readToken_lt_gt(code);
case 61:
case 33: // '=!'
return this.readToken_eq_excl(code);
case 126: // '~'
return this.finishOp(tt.tilde, 1);
}
this.raise(
this.state.pos,
`Unexpected character '${codePointToString(code)}'`,
);
}
finishOp(type: TokenType, size: number): void {
const str = this.input.slice(this.state.pos, this.state.pos + size);
this.state.pos += size;
return this.finishToken(type, str);
}
readRegexp(): void {
const start = this.state.pos;
let escaped, inClass;
for (;;) {
if (this.state.pos >= this.input.length)
this.raise(start, "Unterminated regular expression");
const ch = this.input.charAt(this.state.pos);
if (lineBreak.test(ch)) {
this.raise(start, "Unterminated regular expression");
}
if (escaped) {
escaped = false;
} else {
if (ch === "[") {
inClass = true;
} else if (ch === "]" && inClass) {
inClass = false;
} else if (ch === "/" && !inClass) {
break;
}
escaped = ch === "\\";
}
++this.state.pos;
}
const content = this.input.slice(start, this.state.pos);
++this.state.pos;
// Need to use `readWord1` because '\uXXXX' sequences are allowed
// here (don't ask).
const mods = this.readWord1();
if (mods) {
const validFlags = /^[gmsiyu]*$/;
if (!validFlags.test(mods))
this.raise(start, "Invalid regular expression flag");
}
return this.finishToken(tt.regexp, {
pattern: content,
flags: mods,
});
}
// Read an integer in the given radix. Return null if zero digits
// were read, the integer value otherwise. When `len` is given, this
// will return `null` unless the integer has exactly `len` digits.
readInt(radix: number, len?: number): number | null {
const start = this.state.pos;
const forbiddenSiblings =
radix === 16
? forbiddenNumericSeparatorSiblings.hex
: forbiddenNumericSeparatorSiblings.decBinOct;
let total = 0;
for (let i = 0, e = len == null ? Infinity : len; i < e; ++i) {
const code = this.input.charCodeAt(this.state.pos);
let val;
if (this.hasPlugin("numericSeparator")) {
const prev = this.input.charCodeAt(this.state.pos - 1);
const next = this.input.charCodeAt(this.state.pos + 1);
if (code === 95) {
if (
forbiddenSiblings.indexOf(prev) > -1 ||
forbiddenSiblings.indexOf(next) > -1 ||
Number.isNaN(next)
) {
this.raise(this.state.pos, "Invalid NumericLiteralSeparator");
}
// Ignore this _ character
++this.state.pos;
continue;
}
}
if (code >= 97) {
val = code - 97 + 10; // a
} else if (code >= 65) {
val = code - 65 + 10; // A
} else if (code >= 48 && code <= 57) {
val = code - 48; // 0-9
} else {
val = Infinity;
}
if (val >= radix) break;
++this.state.pos;
total = total * radix + val;
}
if (
this.state.pos === start ||
(len != null && this.state.pos - start !== len)
)
return null;
return total;
}
readRadixNumber(radix: number): void {
const start = this.state.pos;
let isBigInt = false;
this.state.pos += 2; // 0x
const val = this.readInt(radix);
if (val == null)
this.raise(this.state.start + 2, "Expected number in radix " + radix);
if (this.hasPlugin("bigInt")) {
if (this.input.charCodeAt(this.state.pos) === 0x6e) {
// 'n'
++this.state.pos;
isBigInt = true;
}
}
if (isIdentifierStart(this.fullCharCodeAtPos()))
this.raise(this.state.pos, "Identifier directly after number");
if (isBigInt) {
const str = this.input.slice(start, this.state.pos).replace(/[_n]/g, "");
return this.finishToken(tt.bigint, str);
}
return this.finishToken(tt.num, val);
}
// Read an integer, octal integer, or floating-point number.
readNumber(startsWithDot: boolean): void {
const start = this.state.pos;
let octal = this.input.charCodeAt(start) === 0x30; // '0'
let isFloat = false;
let isBigInt = false;
if (!startsWithDot && this.readInt(10) === null)
this.raise(start, "Invalid number");
if (octal && this.state.pos == start + 1) octal = false; // number === 0
let next = this.input.charCodeAt(this.state.pos);
if (next === 0x2e && !octal) {
// '.'
++this.state.pos;
this.readInt(10);
isFloat = true;
next = this.input.charCodeAt(this.state.pos);
}
if ((next === 0x45 || next === 0x65) && !octal) {
// 'Ee'
next = this.input.charCodeAt(++this.state.pos);
if (next === 0x2b || next === 0x2d) ++this.state.pos; // '+-'
if (this.readInt(10) === null) this.raise(start, "Invalid number");
isFloat = true;
next = this.input.charCodeAt(this.state.pos);
}
if (this.hasPlugin("bigInt")) {
if (next === 0x6e) {
// 'n'
// disallow floats and legacy octal syntax, new style octal ("0o") is handled in this.readRadixNumber
if (isFloat || octal) this.raise(start, "Invalid BigIntLiteral");
++this.state.pos;
isBigInt = true;
}
}
if (isIdentifierStart(this.fullCharCodeAtPos()))
this.raise(this.state.pos, "Identifier directly after number");
// remove "_" for numeric literal separator, and "n" for BigInts
const str = this.input.slice(start, this.state.pos).replace(/[_n]/g, "");
if (isBigInt) {
return this.finishToken(tt.bigint, str);
}
let val;
if (isFloat) {
val = parseFloat(str);
} else if (!octal || str.length === 1) {
val = parseInt(str, 10);
} else if (this.state.strict) {
this.raise(start, "Invalid number");
} else if (/[89]/.test(str)) {
val = parseInt(str, 10);
} else {
val = parseInt(str, 8);
}
return this.finishToken(tt.num, val);
}
// Read a string value, interpreting backslash-escapes.
readCodePoint(throwOnInvalid: boolean): number | null {
const ch = this.input.charCodeAt(this.state.pos);
let code;
if (ch === 123) {
// '{'
const codePos = ++this.state.pos;
code = this.readHexChar(
this.input.indexOf("}", this.state.pos) - this.state.pos,
throwOnInvalid,
);
++this.state.pos;
if (code === null) {
// $FlowFixMe (is this always non-null?)
--this.state.invalidTemplateEscapePosition; // to point to the '\'' instead of the 'u'
} else if (code > 0x10ffff) {
if (throwOnInvalid) {
this.raise(codePos, "Code point out of bounds");
} else {
this.state.invalidTemplateEscapePosition = codePos - 2;
return null;
}
}
} else {
code = this.readHexChar(4, throwOnInvalid);
}
return code;
}
readString(quote: number): void {
let out = "",
chunkStart = ++this.state.pos;
for (;;) {
if (this.state.pos >= this.input.length)
this.raise(this.state.start, "Unterminated string constant");
const ch = this.input.charCodeAt(this.state.pos);
if (ch === quote) break;
if (ch === 92) {
// '\'
out += this.input.slice(chunkStart, this.state.pos);
// $FlowFixMe
out += this.readEscapedChar(false);
chunkStart = this.state.pos;
} else {
if (isNewLine(ch))
this.raise(this.state.start, "Unterminated string constant");
++this.state.pos;
}
}
out += this.input.slice(chunkStart, this.state.pos++);
return this.finishToken(tt.string, out);
}
// Reads template string tokens.
readTmplToken(): void {
let out = "",
chunkStart = this.state.pos,
containsInvalid = false;
for (;;) {
if (this.state.pos >= this.input.length)
this.raise(this.state.start, "Unterminated template");
const ch = this.input.charCodeAt(this.state.pos);
if (
ch === 96 ||
(ch === 36 && this.input.charCodeAt(this.state.pos + 1) === 123)
) {
// '`', '${'
if (this.state.pos === this.state.start && this.match(tt.template)) {
if (ch === 36) {
this.state.pos += 2;
return this.finishToken(tt.dollarBraceL);
} else {
++this.state.pos;
return this.finishToken(tt.backQuote);
}
}
out += this.input.slice(chunkStart, this.state.pos);
return this.finishToken(tt.template, containsInvalid ? null : out);
}
if (ch === 92) {
// '\'
out += this.input.slice(chunkStart, this.state.pos);
const escaped = this.readEscapedChar(true);
if (escaped === null) {
containsInvalid = true;
} else {
out += escaped;
}
chunkStart = this.state.pos;
} else if (isNewLine(ch)) {
out += this.input.slice(chunkStart, this.state.pos);
++this.state.pos;
switch (ch) {
case 13:
if (this.input.charCodeAt(this.state.pos) === 10) ++this.state.pos;
case 10:
out += "\n";
break;
default:
out += String.fromCharCode(ch);
break;
}
++this.state.curLine;
this.state.lineStart = this.state.pos;
chunkStart = this.state.pos;
} else {
++this.state.pos;
}
}
}
// Used to read escaped characters
readEscapedChar(inTemplate: boolean): string | null {
const throwOnInvalid = !inTemplate;
const ch = this.input.charCodeAt(++this.state.pos);
++this.state.pos;
switch (ch) {
case 110:
return "\n"; // 'n' -> '\n'
case 114:
return "\r"; // 'r' -> '\r'
case 120: {
// 'x'
const code = this.readHexChar(2, throwOnInvalid);
return code === null ? null : String.fromCharCode(code);
}
case 117: {
// 'u'
const code = this.readCodePoint(throwOnInvalid);
return code === null ? null : codePointToString(code);
}
case 116:
return "\t"; // 't' -> '\t'
case 98:
return "\b"; // 'b' -> '\b'
case 118:
return "\u000b"; // 'v' -> '\u000b'
case 102:
return "\f"; // 'f' -> '\f'
case 13:
if (this.input.charCodeAt(this.state.pos) === 10) ++this.state.pos; // '\r\n'
case 10: // ' \n'
this.state.lineStart = this.state.pos;
++this.state.curLine;
return "";
default:
if (ch >= 48 && ch <= 55) {
const codePos = this.state.pos - 1;
// $FlowFixMe
let octalStr = this.input
.substr(this.state.pos - 1, 3)
.match(/^[0-7]+/)[0];
let octal = parseInt(octalStr, 8);
if (octal > 255) {
octalStr = octalStr.slice(0, -1);
octal = parseInt(octalStr, 8);
}
if (octal > 0) {
if (inTemplate) {
this.state.invalidTemplateEscapePosition = codePos;
return null;
} else if (this.state.strict) {
this.raise(codePos, "Octal literal in strict mode");
} else if (!this.state.containsOctal) {
// These properties are only used to throw an error for an octal which occurs
// in a directive which occurs prior to a "use strict" directive.
this.state.containsOctal = true;
this.state.octalPosition = codePos;
}
}
this.state.pos += octalStr.length - 1;
return String.fromCharCode(octal);
}
return String.fromCharCode(ch);
}
}
// Used to read character escape sequences ('\x', '\u').
readHexChar(len: number, throwOnInvalid: boolean): number | null {
const codePos = this.state.pos;
const n = this.readInt(16, len);
if (n === null) {
if (throwOnInvalid) {
this.raise(codePos, "Bad character escape sequence");
} else {
this.state.pos = codePos - 1;
this.state.invalidTemplateEscapePosition = codePos - 1;
}
}
return n;
}
// Read an identifier, and return it as a string. Sets `this.state.containsEsc`
// to whether the word contained a '\u' escape.
//
// Incrementally adds only escaped chars, adding other chunks as-is
// as a micro-optimization.
readWord1(): string {
this.state.containsEsc = false;
let word = "",
first = true,
chunkStart = this.state.pos;
while (this.state.pos < this.input.length) {
const ch = this.fullCharCodeAtPos();
if (isIdentifierChar(ch)) {
this.state.pos += ch <= 0xffff ? 1 : 2;
} else if (ch === 92) {
// "\"
this.state.containsEsc = true;
word += this.input.slice(chunkStart, this.state.pos);
const escStart = this.state.pos;
if (this.input.charCodeAt(++this.state.pos) !== 117) {
// "u"
this.raise(
this.state.pos,
"Expecting Unicode escape sequence \\uXXXX",
);
}
++this.state.pos;
const esc = this.readCodePoint(true);
// $FlowFixMe (thinks esc may be null, but throwOnInvalid is true)
if (!(first ? isIdentifierStart : isIdentifierChar)(esc, true)) {
this.raise(escStart, "Invalid Unicode escape");
}
// $FlowFixMe
word += codePointToString(esc);
chunkStart = this.state.pos;
} else {
break;
}
first = false;
}
return word + this.input.slice(chunkStart, this.state.pos);
}
// Read an identifier or keyword token. Will check for reserved
// words when necessary.
readWord(): void {
const word = this.readWord1();
let type = tt.name;
if (this.isKeyword(word)) {
if (this.state.containsEsc) {
this.raise(this.state.pos, `Escape sequence in keyword ${word}`);
}
type = keywordTypes[word];
}
return this.finishToken(type, word);
}
braceIsBlock(prevType: TokenType): boolean {
if (prevType === tt.colon) {
const parent = this.curContext();
if (parent === ct.braceStatement || parent === ct.braceExpression) {
return !parent.isExpr;
}
}
if (prevType === tt._return) {
return lineBreak.test(
this.input.slice(this.state.lastTokEnd, this.state.start),
);
}
if (
prevType === tt._else ||
prevType === tt.semi ||
prevType === tt.eof ||
prevType === tt.parenR
) {
return true;
}
if (prevType === tt.braceL) {
return this.curContext() === ct.braceStatement;
}
if (prevType === tt.relational) {
// `class C<T> { ... }`
return true;
}
return !this.state.exprAllowed;
}
updateContext(prevType: TokenType): void {
const type = this.state.type;
let update;
if (type.keyword && (prevType === tt.dot || prevType === tt.questionDot)) {
this.state.exprAllowed = false;
} else if ((update = type.updateContext)) {
update.call(this, prevType);
} else {
this.state.exprAllowed = type.beforeExpr;
}
}
}