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arvarv
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Setup module.exports first (#2129)
This gives some much needed love to the CommonJS module output. Most importantly it mutates the `module.exports` object before the code is executed which allows some cyclic dependencies to work (function declarations). This also changes the transformer to work on the original code instead of the already transformed code (from `ModuleTransformer`). Things have been refactored so that more code is shared between `CommonJsModuleTransformer` and `ModuleTransformer`. Also, the require variable binding (with `__esModule`) has changed so that we do not need temp variables (outside what is needed for destructuring).
1 parent 79fa394 commit 2ddade7

11 files changed

+158
-172
lines changed

‎src/codegeneration/AmdTransformer.js

+1-1
Original file line numberDiff line numberDiff line change
@@ -48,7 +48,7 @@ export class AmdTransformer extends ModuleTransformer {
4848
getExportProperties() {
4949
let properties = super.getExportProperties();
5050

51-
if (this.exportVisitor_.hasExports())
51+
if (this.exportVisitor.hasExports())
5252
properties.push(parsePropertyDefinition `__esModule: true`);
5353
return properties;
5454
}

‎src/codegeneration/ClosureModuleTransformer.js

+1-1
Original file line numberDiff line numberDiff line change
@@ -53,7 +53,7 @@ export class ClosureModuleTransformer extends ModuleTransformer {
5353
return statements;
5454
}
5555

56-
appendExportStatement(statements) {
56+
addExportStatement(statements) {
5757
if (!this.hasExports()) return statements;
5858
let exportObject = this.getExportObject();
5959
statements.push(parseStatement `exports = ${exportObject}`);

‎src/codegeneration/CommonJsModuleTransformer.js

+90-105
Original file line numberDiff line numberDiff line change
@@ -13,44 +13,30 @@
1313
// limitations under the License.
1414

1515
import {ModuleTransformer} from './ModuleTransformer.js';
16-
import {
17-
CALL_EXPRESSION,
18-
GET_ACCESSOR,
19-
OBJECT_LITERAL,
20-
PROPERTY_NAME_ASSIGNMENT,
21-
RETURN_STATEMENT
22-
} from '../syntax/trees/ParseTreeType.js';
23-
import {
24-
ArgumentList,
25-
CallExpression,
26-
ExpressionStatement
27-
} from '../syntax/trees/ParseTrees.js';
28-
import {assert} from '../util/assert.js';
29-
import globalThis from './globalThis.js';
16+
import {NAMED_EXPORT} from '../syntax/trees/ParseTreeType.js';
17+
import {AnonBlock} from '../syntax/trees/ParseTrees.js';
3018
import {
3119
parseExpression,
3220
parsePropertyDefinition,
33-
parseStatements
21+
parseStatement,
3422
} from './PlaceholderParser.js';
3523
import {
36-
createEmptyParameterList,
37-
createFunctionExpression,
38-
createIdentifierExpression,
24+
createExpressionStatement,
3925
createObjectLiteral,
26+
createObjectLiteralForDescriptor,
4027
createPropertyNameAssignment,
41-
createVariableStatement,
42-
createVariableDeclaration,
43-
createVariableDeclarationList
4428
} from './ParseTreeFactory.js';
45-
import {VAR} from '../syntax/TokenType.js';
29+
import {prependStatements} from './PrependStatements.js';
30+
import {FindVisitor} from './FindVisitor.js';
4631

4732
export class CommonJsModuleTransformer extends ModuleTransformer {
48-
4933
constructor(identifierGenerator, reporter, options = undefined) {
5034
super(identifierGenerator, reporter, options);
51-
this.moduleVars_ = [];
5235
this.anonymousModule =
5336
options && !options.bundle && options.moduleName !== true;
37+
this.namedExportsWithModuleSpecifiers_ = [];
38+
this.isImportingDefault_ = false;
39+
this.needsInteropRequire_ = false;
5440
}
5541

5642
getModuleName(tree) {
@@ -59,106 +45,105 @@ export class CommonJsModuleTransformer extends ModuleTransformer {
5945
return tree.moduleName;
6046
}
6147

62-
moduleProlog() {
63-
let statements = super.moduleProlog();
64-
65-
// declare temp vars in prolog
66-
if (this.moduleVars_.length) {
67-
let tmpVarDeclarations = createVariableStatement(createVariableDeclarationList(VAR,
68-
this.moduleVars_.map((varName) => createVariableDeclaration(varName, null))));
69-
70-
statements.push(tmpVarDeclarations);
48+
wrapModule(statements) {
49+
if (this.needsInteropRequire_) {
50+
const req = parseStatement `function $__interopRequire(id) {
51+
id = require(id);
52+
return id && id.__esModule && id || {default: id};
53+
}`;
54+
return prependStatements(statements, req);
7155
}
72-
7356
return statements;
7457
}
7558

76-
wrapModule(statements) {
77-
let last = statements[statements.length - 1];
78-
statements = statements.slice(0, -1);
79-
assert(last.type === RETURN_STATEMENT);
80-
let exportExpression = last.expression;
81-
82-
// If the module doesn't use any export statements, nor global "this", it
83-
// might be because it wants to make its own changes to "exports" or
84-
// "module.exports", so we don't append "module.exports = {}" to the output.
85-
if (this.hasExports()) {
86-
let exportStatement =
87-
this.transformExportExpressionToModuleExport(exportExpression);
88-
statements = statements.concat(exportStatement);
59+
addExportStatement(statements) {
60+
if (!this.hasExports()) {
61+
return statements;
8962
}
90-
return statements;
91-
}
9263

93-
transformExportExpressionToModuleExport(tree) {
94-
let expression;
95-
96-
// $traceurRuntime.exportStar({}, ...)
97-
if (tree.type === CALL_EXPRESSION) {
98-
let descriptors =
99-
this.transformObjectLiteralToDescriptors(tree.args.args[0]);
100-
let object = parseExpression
101-
`Object.defineProperties(module.exports, ${descriptors})`;
102-
let newArgs = new ArgumentList(tree.args.location,
103-
[object, ...tree.args.args.slice(1)])
104-
expression = new CallExpression(tree.location, tree.operand, newArgs);
105-
} else {
106-
let descriptors = this.transformObjectLiteralToDescriptors(tree);
107-
expression = parseExpression
108-
`Object.defineProperties(module.exports, ${descriptors})`;
64+
const descr = this.getExportDescriptors();
65+
let exportObject = parseExpression
66+
`Object.defineProperties(module.exports, ${descr})`;
67+
if (this.hasStarExports()) {
68+
exportObject = this.getExportStar(exportObject);
10969
}
11070

111-
return new ExpressionStatement(expression.location, expression);
71+
// Mutate module.exports immediately after all the export star are
72+
// imported, before any module code is executed, to allow some cyclic
73+
// dependencies to work.
74+
return prependStatements(statements,
75+
...this.namedExportsWithModuleSpecifiers_,
76+
createExpressionStatement(exportObject));
11277
}
11378

114-
transformObjectLiteralToDescriptors(literalTree) {
115-
assert(literalTree.type === OBJECT_LITERAL);
116-
117-
let props = literalTree.propertyNameAndValues.map((exp) => {
118-
let descriptor;
119-
120-
switch (exp.type) {
121-
case GET_ACCESSOR: {
122-
let getterFunction =
123-
createFunctionExpression(createEmptyParameterList(), exp.body);
124-
descriptor =
125-
parseExpression `{get: ${getterFunction}, enumerable: true}`;
126-
break;
127-
}
79+
getExportDescriptors() {
80+
// {
81+
// x: {
82+
// enumerable: true,
83+
// get: function() { ... },
84+
// },
85+
// ...
86+
// }
87+
88+
const properties = this.exportVisitor.getNonTypeNamedExports().map(exp => {
89+
const f = parseExpression `function() { return ${
90+
this.getGetterExportReturnExpression(exp)
91+
}; }`;
92+
return createPropertyNameAssignment(exp.name,
93+
createObjectLiteralForDescriptor({enumerable: true, get: f}));
94+
});
95+
properties.unshift(parsePropertyDefinition `__esModule: {value: true}`);
96+
return createObjectLiteral(properties);
97+
}
12898

129-
case PROPERTY_NAME_ASSIGNMENT:
130-
descriptor = parseExpression `{value: ${exp.value}}`;
131-
break;
99+
transformExportDeclaration(tree) {
100+
this.checkForDefaultImport_(tree);
101+
this.exportVisitor.visitAny(tree);
102+
const transformed = this.transformAny(tree.declaration);
103+
104+
// Need to output the require for export ? from moduleSpecifier before
105+
// the call to exportStar.
106+
if (tree.declaration.type == NAMED_EXPORT &&
107+
tree.declaration.moduleSpecifier !== null) {
108+
this.namedExportsWithModuleSpecifiers_.push(transformed);
109+
return new AnonBlock(null, []);
110+
}
132111

133-
default:
134-
throw new Error(`Unexpected property type ${exp.type}`);
135-
}
112+
return transformed;
113+
}
136114

137-
return createPropertyNameAssignment(exp.name, descriptor);
138-
});
115+
transformImportDeclaration(tree) {
116+
this.checkForDefaultImport_(tree);
117+
return super.transformImportDeclaration(tree);
118+
}
139119

140-
return createObjectLiteral(props);
120+
checkForDefaultImport_(tree) {
121+
const finder = new FindDefault();
122+
finder.visitAny(tree);
123+
this.isImportingDefault_ = finder.found;
141124
}
142125

143126
transformModuleSpecifier(tree) {
144127
let moduleName = tree.token.processedValue;
145-
let tmpVar = this.getTempVarNameForModuleSpecifier(tree);
146-
this.moduleVars_.push(tmpVar);
147-
let tvId = createIdentifierExpression(tmpVar);
148-
149-
// require the module, if it is not marked as an ES6 module, treat it as { default: module }
150-
// this allows for an unlinked CommonJS / ES6 interop
151-
// note that future implementations should also check for native Module with
152-
// Reflect.isModule or similar
153-
return parseExpression `(${tvId} = require(${moduleName}),
154-
${tvId} && ${tvId}.__esModule && ${tvId} || {default: ${tvId}})`;
128+
if (this.isImportingDefault_) {
129+
this.needsInteropRequire_ = true;
130+
return parseExpression `$__interopRequire(${moduleName})`;
131+
}
132+
return parseExpression `require(${moduleName})`;
155133
}
134+
}
156135

157-
getExportProperties() {
158-
let properties = super.getExportProperties();
159-
160-
if (this.exportVisitor_.hasExports())
161-
properties.push(parsePropertyDefinition `__esModule: true`);
162-
return properties;
136+
class FindDefault extends FindVisitor {
137+
visitImportSpecifier(tree) {
138+
this.found = tree.name !== null && tree.name.value === 'default';
139+
}
140+
visitNameSpaceImport(tree) {
141+
this.found = true;
142+
}
143+
visitNameSpaceExport(tree) {
144+
this.found = true;
145+
}
146+
visitExportSpecifier(tree) {
147+
this.found = tree.lhs !== null && tree.lhs.value === 'default';
163148
}
164149
}

‎src/codegeneration/InlineES6ModuleTransformer.js

+4-4
Original file line numberDiff line numberDiff line change
@@ -117,7 +117,7 @@ export class InlineES6ModuleTransformer extends ModuleTransformer {
117117
if (this.isRootModule)
118118
return tree;
119119

120-
this.exportVisitor_.visitAny(tree);
120+
this.exportVisitor.visitAny(tree);
121121
return this.transformAny(tree.declaration);
122122
}
123123

@@ -154,11 +154,11 @@ export class InlineES6ModuleTransformer extends ModuleTransformer {
154154
*
155155
* @returns {Array} statements
156156
*/
157-
appendExportStatement(statements) {
157+
addExportStatement(statements) {
158158
let exportProperties = this.getExportProperties();
159159
let exportObject = createObjectLiteral(exportProperties);
160-
if (this.exportVisitor_.starExports.length) {
161-
let starExports = this.exportVisitor_.starExports;
160+
if (this.exportVisitor.starExports.length) {
161+
let starExports = this.exportVisitor.starExports;
162162
let starIdents = starExports.map((moduleSpecifier) => {
163163
return createIdentifierExpression(
164164
this.getTempVarNameForModuleSpecifier(moduleSpecifier));

‎src/codegeneration/InstantiateModuleTransformer.js

+1-1
Original file line numberDiff line numberDiff line change
@@ -362,7 +362,7 @@ export class InstantiateModuleTransformer extends ModuleTransformer {
362362
* });
363363
*
364364
*/
365-
appendExportStatement(statements) {
365+
addExportStatement(statements) {
366366
let declarationExtractionTransformer = new DeclarationExtractionTransformer();
367367

368368
// convert __moduleName identifiers into $__moduleContext.id

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