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[ts] Insert export {} when necessary to imply ESM (#13314)

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Will Binns-Smith 2021-05-20 15:54:39 -07:00 committed by GitHub
parent f0b9b25a23
commit b4c798e754
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15 changed files with 149 additions and 92 deletions
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224
packages/babel-plugin-transform-typescript/src/index.ts
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@ -21,8 +21,12 @@ function isInType(path) {
} }
} }
const PARSED_PARAMS = new WeakSet();
const GLOBAL_TYPES = new WeakMap(); const GLOBAL_TYPES = new WeakMap();
// Track programs which contain imports/exports of values, so that we can include
// empty exports for programs that do not, but were parsed as modules. This allows
// tools to infer unamibiguously that results are ESM.
const NEEDS_EXPLICIT_ESM = new WeakMap();
const PARSED_PARAMS = new WeakSet();
function isGlobalType(path, name) { function isGlobalType(path, name) {
const program = path.find(path => path.isProgram()).node; const program = path.find(path => path.isProgram()).node;
@ -175,118 +179,143 @@ export default declare((api, opts) => {
Identifier: visitPattern, Identifier: visitPattern,
RestElement: visitPattern, RestElement: visitPattern,
Program(path, state) { Program: {
const { file } = state; enter(path, state) {
let fileJsxPragma = null; const { file } = state;
let fileJsxPragmaFrag = null; let fileJsxPragma = null;
let fileJsxPragmaFrag = null;
if (!GLOBAL_TYPES.has(path.node)) { if (!GLOBAL_TYPES.has(path.node)) {
GLOBAL_TYPES.set(path.node, new Set()); GLOBAL_TYPES.set(path.node, new Set());
} }
if (file.ast.comments) { if (file.ast.comments) {
for (const comment of file.ast.comments) { for (const comment of file.ast.comments) {
const jsxMatches = JSX_PRAGMA_REGEX.exec(comment.value); const jsxMatches = JSX_PRAGMA_REGEX.exec(comment.value);
if (jsxMatches) { if (jsxMatches) {
if (jsxMatches[1]) { if (jsxMatches[1]) {
// isFragment // isFragment
fileJsxPragmaFrag = jsxMatches[2]; fileJsxPragmaFrag = jsxMatches[2];
} else { } else {
fileJsxPragma = jsxMatches[2]; fileJsxPragma = jsxMatches[2];
}
} }
} }
} }
}
let pragmaImportName = fileJsxPragma || jsxPragma; let pragmaImportName = fileJsxPragma || jsxPragma;
if (pragmaImportName) { if (pragmaImportName) {
[pragmaImportName] = pragmaImportName.split("."); [pragmaImportName] = pragmaImportName.split(".");
} }
let pragmaFragImportName = fileJsxPragmaFrag || jsxPragmaFrag; let pragmaFragImportName = fileJsxPragmaFrag || jsxPragmaFrag;
if (pragmaFragImportName) { if (pragmaFragImportName) {
[pragmaFragImportName] = pragmaFragImportName.split("."); [pragmaFragImportName] = pragmaFragImportName.split(".");
} }
// remove type imports // remove type imports
for (let stmt of path.get("body")) { for (let stmt of path.get("body")) {
if (stmt.isImportDeclaration()) { if (stmt.isImportDeclaration()) {
if (stmt.node.importKind === "type") { if (!NEEDS_EXPLICIT_ESM.has(state.file.ast.program)) {
stmt.remove(); NEEDS_EXPLICIT_ESM.set(state.file.ast.program, true);
continue; }
}
// If onlyRemoveTypeImports is `true`, only remove type-only imports if (stmt.node.importKind === "type") {
// and exports introduced in TypeScript 3.8. stmt.remove();
if (!onlyRemoveTypeImports) {
// Note: this will allow both `import { } from "m"` and `import "m";`.
// In TypeScript, the former would be elided.
if (stmt.node.specifiers.length === 0) {
continue; continue;
} }
let allElided = true; // If onlyRemoveTypeImports is `true`, only remove type-only imports
const importsToRemove: NodePath<t.Node>[] = []; // and exports introduced in TypeScript 3.8.
if (onlyRemoveTypeImports) {
for (const specifier of stmt.node.specifiers) { NEEDS_EXPLICIT_ESM.set(path.node, false);
const binding = stmt.scope.getBinding(specifier.local.name);
// The binding may not exist if the import node was explicitly
// injected by another plugin. Currently core does not do a good job
// of keeping scope bindings synchronized with the AST. For now we
// just bail if there is no binding, since chances are good that if
// the import statement was injected then it wasn't a typescript type
// import anyway.
if (
binding &&
isImportTypeOnly({
binding,
programPath: path,
pragmaImportName,
pragmaFragImportName,
})
) {
importsToRemove.push(binding.path);
} else {
allElided = false;
}
}
if (allElided) {
stmt.remove();
} else { } else {
for (const importPath of importsToRemove) { // Note: this will allow both `import { } from "m"` and `import "m";`.
importPath.remove(); // In TypeScript, the former would be elided.
if (stmt.node.specifiers.length === 0) {
NEEDS_EXPLICIT_ESM.set(path.node, false);
continue;
}
let allElided = true;
const importsToRemove: NodePath<t.Node>[] = [];
for (const specifier of stmt.node.specifiers) {
const binding = stmt.scope.getBinding(specifier.local.name);
// The binding may not exist if the import node was explicitly
// injected by another plugin. Currently core does not do a good job
// of keeping scope bindings synchronized with the AST. For now we
// just bail if there is no binding, since chances are good that if
// the import statement was injected then it wasn't a typescript type
// import anyway.
if (
binding &&
isImportTypeOnly({
binding,
programPath: path,
pragmaImportName,
pragmaFragImportName,
})
) {
importsToRemove.push(binding.path);
} else {
allElided = false;
NEEDS_EXPLICIT_ESM.set(path.node, false);
}
}
if (allElided) {
stmt.remove();
} else {
for (const importPath of importsToRemove) {
importPath.remove();
}
} }
} }
continue;
} }
continue; if (stmt.isExportDeclaration()) {
} stmt = stmt.get("declaration");
if (stmt.isExportDeclaration()) {
stmt = stmt.get("declaration");
}
if (stmt.isVariableDeclaration({ declare: true })) {
for (const name of Object.keys(stmt.getBindingIdentifiers())) {
registerGlobalType(path.scope, name);
} }
} else if (
stmt.isTSTypeAliasDeclaration() || if (stmt.isVariableDeclaration({ declare: true })) {
stmt.isTSDeclareFunction() || for (const name of Object.keys(stmt.getBindingIdentifiers())) {
stmt.isTSInterfaceDeclaration() || registerGlobalType(path.scope, name);
stmt.isClassDeclaration({ declare: true }) || }
stmt.isTSEnumDeclaration({ declare: true }) || } else if (
(stmt.isTSModuleDeclaration({ declare: true }) && stmt.isTSTypeAliasDeclaration() ||
stmt.get("id").isIdentifier()) stmt.isTSDeclareFunction() ||
stmt.isTSInterfaceDeclaration() ||
stmt.isClassDeclaration({ declare: true }) ||
stmt.isTSEnumDeclaration({ declare: true }) ||
(stmt.isTSModuleDeclaration({ declare: true }) &&
stmt.get("id").isIdentifier())
) {
registerGlobalType(path.scope, stmt.node.id.name);
}
}
},
exit(path) {
if (
path.node.sourceType === "module" &&
NEEDS_EXPLICIT_ESM.get(path.node)
) { ) {
registerGlobalType(path.scope, stmt.node.id.name); // If there are no remaining value exports, this file can no longer
// be inferred to be ESM. Leave behind an empty export declaration
// so it can be.
path.pushContainer("body", t.exportNamedDeclaration());
} }
} },
}, },
ExportNamedDeclaration(path) { ExportNamedDeclaration(path, state) {
if (!NEEDS_EXPLICIT_ESM.has(state.file.ast.program)) {
NEEDS_EXPLICIT_ESM.set(state.file.ast.program, true);
}
if (path.node.exportKind === "type") { if (path.node.exportKind === "type") {
path.remove(); path.remove();
return; return;
@ -307,7 +336,10 @@ export default declare((api, opts) => {
) )
) { ) {
path.remove(); path.remove();
return;
} }
NEEDS_EXPLICIT_ESM.set(state.file.ast.program, false);
}, },
ExportSpecifier(path) { ExportSpecifier(path) {
@ -317,14 +349,22 @@ export default declare((api, opts) => {
} }
}, },
ExportDefaultDeclaration(path) { ExportDefaultDeclaration(path, state) {
if (!NEEDS_EXPLICIT_ESM.has(state.file.ast.program)) {
NEEDS_EXPLICIT_ESM.set(state.file.ast.program, true);
}
// remove whole declaration if it's exporting a TS type // remove whole declaration if it's exporting a TS type
if ( if (
t.isIdentifier(path.node.declaration) && t.isIdentifier(path.node.declaration) &&
isGlobalType(path, path.node.declaration.name) isGlobalType(path, path.node.declaration.name)
) { ) {
path.remove(); path.remove();
return;
} }
NEEDS_EXPLICIT_ESM.set(state.file.ast.program, false);
}, },
TSDeclareFunction(path) { TSDeclareFunction(path) {

2
packages/babel-plugin-transform-typescript/test/fixtures/declarations/erased/output.mjs vendored
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@ -1 +1,3 @@
; // Otherwise-empty file ; // Otherwise-empty file
export {};

2
packages/babel-plugin-transform-typescript/test/fixtures/declarations/nested-namespace/output.mjs vendored
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@ -1 +1,3 @@
; // Otherwise-empty file ; // Otherwise-empty file
export {};

1
packages/babel-plugin-transform-typescript/test/fixtures/exports/export-type-from/output.mjs vendored
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@ -1 +1,2 @@
; ;
export {};

1
packages/babel-plugin-transform-typescript/test/fixtures/exports/export-type/output.mjs vendored
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@ -1 +1,2 @@
; ;
export {};

1
packages/babel-plugin-transform-typescript/test/fixtures/imports/elide-preact/output.mjs vendored
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@ -1 +1,2 @@
const x = 0; const x = 0;
export {};

1
packages/babel-plugin-transform-typescript/test/fixtures/imports/elide-react/output.mjs vendored
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@ -1 +1,2 @@
const x = 0; const x = 0;
export {};

1
packages/babel-plugin-transform-typescript/test/fixtures/imports/elide-typeof/output.mjs vendored
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@ -1 +1,2 @@
const x = 0; const x = 0;
export {};

1
packages/babel-plugin-transform-typescript/test/fixtures/imports/elision-qualifiedname/output.mjs vendored
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@ -1 +1,2 @@
const x = 0; const x = 0;
export {};

1
packages/babel-plugin-transform-typescript/test/fixtures/imports/elision-rename/output.mjs vendored
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@ -1 +1,2 @@
const x = 0; const x = 0;
export {};

1
packages/babel-plugin-transform-typescript/test/fixtures/imports/enum-id/output.mjs vendored
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@ -5,3 +5,4 @@ var Enum;
})(Enum || (Enum = {})); })(Enum || (Enum = {}));
; ;
export {};

1
packages/babel-plugin-transform-typescript/test/fixtures/imports/import-type-not-removed/output.mjs vendored
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@ -1,2 +1,3 @@
// TODO: This should not be removed // TODO: This should not be removed
; ;
export {};

1
packages/babel-plugin-transform-typescript/test/fixtures/imports/import-type/output.mjs vendored
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@ -1 +1,2 @@
; ;
export {};

1
packages/babel-plugin-transform-typescript/test/fixtures/imports/property-signature/output.mjs vendored
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@ -1,3 +1,4 @@
const obj = { const obj = {
A: 'foo' A: 'foo'
}; };
export {};

2
packages/babel-plugin-transform-typescript/test/fixtures/namespace/canonical/output.mjs vendored
View File

@ -37,3 +37,5 @@ for (let s of strings) {
console.log(`"${s}" - ${validators[name].isAcceptable(s) ? "matches" : "does not match"} ${name}`); console.log(`"${s}" - ${validators[name].isAcceptable(s) ? "matches" : "does not match"} ${name}`);
} }
} }
export {};