mirror of https://github.com/webpack/webpack.git
412 lines
14 KiB
JavaScript
412 lines
14 KiB
JavaScript
/*
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MIT License http://www.opensource.org/licenses/mit-license.php
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Author Tobias Koppers @sokra
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*/
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"use strict";
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const RuntimeGlobals = require("../RuntimeGlobals");
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const formatLocation = require("../formatLocation");
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const { evaluateToString } = require("../javascript/JavascriptParserHelpers");
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const propertyAccess = require("../util/propertyAccess");
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const CommonJsExportRequireDependency = require("./CommonJsExportRequireDependency");
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const CommonJsExportsDependency = require("./CommonJsExportsDependency");
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const CommonJsSelfReferenceDependency = require("./CommonJsSelfReferenceDependency");
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const DynamicExports = require("./DynamicExports");
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const HarmonyExports = require("./HarmonyExports");
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const ModuleDecoratorDependency = require("./ModuleDecoratorDependency");
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/** @typedef {import("estree").AssignmentExpression} AssignmentExpression */
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/** @typedef {import("estree").CallExpression} CallExpression */
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/** @typedef {import("estree").Expression} Expression */
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/** @typedef {import("estree").Super} Super */
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/** @typedef {import("../Dependency").DependencyLocation} DependencyLocation */
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/** @typedef {import("../ModuleGraph")} ModuleGraph */
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/** @typedef {import("../NormalModule")} NormalModule */
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/** @typedef {import("../javascript/BasicEvaluatedExpression")} BasicEvaluatedExpression */
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/** @typedef {import("../javascript/JavascriptParser")} JavascriptParser */
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/** @typedef {import("../javascript/JavascriptParser").Range} Range */
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/** @typedef {import("../javascript/JavascriptParser").StatementPath} StatementPath */
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/** @typedef {import("./CommonJsDependencyHelpers").CommonJSDependencyBaseKeywords} CommonJSDependencyBaseKeywords */
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/**
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* This function takes a generic expression and detects whether it is an ObjectExpression.
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* This is used in the context of parsing CommonJS exports to get the value of the property descriptor
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* when the `exports` object is assigned to `Object.defineProperty`.
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*
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* In CommonJS modules, the `exports` object can be assigned to `Object.defineProperty` and therefore
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* webpack has to detect this case and get the value key of the property descriptor. See the following example
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* for more information: https://astexplorer.net/#/gist/83ce51a4e96e59d777df315a6d111da6/8058ead48a1bb53c097738225db0967ef7f70e57
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*
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* This would be an example of a CommonJS module that exports an object with a property descriptor:
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* ```js
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* Object.defineProperty(exports, "__esModule", { value: true });
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* exports.foo = void 0;
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* exports.foo = "bar";
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* ```
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* @param {TODO} expr expression
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* @returns {Expression | undefined} returns the value of property descriptor
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*/
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const getValueOfPropertyDescription = expr => {
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if (expr.type !== "ObjectExpression") return;
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for (const property of expr.properties) {
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if (property.computed) continue;
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const key = property.key;
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if (key.type !== "Identifier" || key.name !== "value") continue;
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return property.value;
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}
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};
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/**
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* The purpose of this function is to check whether an expression is a truthy literal or not. This is
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* useful when parsing CommonJS exports, because CommonJS modules can export any value, including falsy
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* values like `null` and `false`. However, exports should only be created if the exported value is truthy.
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* @param {Expression} expr expression being checked
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* @returns {boolean} true, when the expression is a truthy literal
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*/
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const isTruthyLiteral = expr => {
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switch (expr.type) {
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case "Literal":
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return Boolean(expr.value);
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case "UnaryExpression":
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if (expr.operator === "!") return isFalsyLiteral(expr.argument);
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}
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return false;
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};
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/**
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* The purpose of this function is to check whether an expression is a falsy literal or not. This is
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* useful when parsing CommonJS exports, because CommonJS modules can export any value, including falsy
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* values like `null` and `false`. However, exports should only be created if the exported value is truthy.
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* @param {Expression} expr expression being checked
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* @returns {boolean} true, when the expression is a falsy literal
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*/
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const isFalsyLiteral = expr => {
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switch (expr.type) {
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case "Literal":
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return !expr.value;
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case "UnaryExpression":
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if (expr.operator === "!") return isTruthyLiteral(expr.argument);
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}
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return false;
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};
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/**
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* @param {JavascriptParser} parser the parser
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* @param {Expression} expr expression
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* @returns {{ argument: BasicEvaluatedExpression, ids: string[] } | undefined} parsed call
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*/
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const parseRequireCall = (parser, expr) => {
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const ids = [];
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while (expr.type === "MemberExpression") {
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if (expr.object.type === "Super") return;
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if (!expr.property) return;
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const prop = expr.property;
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if (expr.computed) {
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if (prop.type !== "Literal") return;
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ids.push(`${prop.value}`);
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} else {
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if (prop.type !== "Identifier") return;
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ids.push(prop.name);
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}
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expr = expr.object;
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}
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if (expr.type !== "CallExpression" || expr.arguments.length !== 1) return;
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const callee = expr.callee;
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if (
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callee.type !== "Identifier" ||
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parser.getVariableInfo(callee.name) !== "require"
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) {
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return;
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}
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const arg = expr.arguments[0];
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if (arg.type === "SpreadElement") return;
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const argValue = parser.evaluateExpression(arg);
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return { argument: argValue, ids: ids.reverse() };
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};
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class CommonJsExportsParserPlugin {
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/**
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* @param {ModuleGraph} moduleGraph module graph
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*/
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constructor(moduleGraph) {
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this.moduleGraph = moduleGraph;
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}
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/**
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* @param {JavascriptParser} parser the parser
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* @returns {void}
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*/
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apply(parser) {
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const enableStructuredExports = () => {
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DynamicExports.enable(parser.state);
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};
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/**
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* @param {boolean} topLevel true, when the export is on top level
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* @param {string[]} members members of the export
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* @param {Expression | undefined} valueExpr expression for the value
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* @returns {void}
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*/
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const checkNamespace = (topLevel, members, valueExpr) => {
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if (!DynamicExports.isEnabled(parser.state)) return;
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if (members.length > 0 && members[0] === "__esModule") {
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if (valueExpr && isTruthyLiteral(valueExpr) && topLevel) {
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DynamicExports.setFlagged(parser.state);
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} else {
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DynamicExports.setDynamic(parser.state);
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}
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}
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};
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/**
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* @param {string=} reason reason
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*/
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const bailout = reason => {
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DynamicExports.bailout(parser.state);
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if (reason) bailoutHint(reason);
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};
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/**
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* @param {string} reason reason
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*/
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const bailoutHint = reason => {
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this.moduleGraph
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.getOptimizationBailout(parser.state.module)
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.push(`CommonJS bailout: ${reason}`);
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};
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// metadata //
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parser.hooks.evaluateTypeof
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.for("module")
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.tap("CommonJsExportsParserPlugin", evaluateToString("object"));
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parser.hooks.evaluateTypeof
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.for("exports")
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.tap("CommonJsPlugin", evaluateToString("object"));
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// exporting //
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/**
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* @param {AssignmentExpression} expr expression
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* @param {CommonJSDependencyBaseKeywords} base commonjs base keywords
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* @param {string[]} members members of the export
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* @returns {boolean | undefined} true, when the expression was handled
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*/
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const handleAssignExport = (expr, base, members) => {
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if (HarmonyExports.isEnabled(parser.state)) return;
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// Handle reexporting
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const requireCall = parseRequireCall(parser, expr.right);
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if (
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requireCall &&
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requireCall.argument.isString() &&
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(members.length === 0 || members[0] !== "__esModule")
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) {
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enableStructuredExports();
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// It's possible to reexport __esModule, so we must convert to a dynamic module
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if (members.length === 0) DynamicExports.setDynamic(parser.state);
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const dep = new CommonJsExportRequireDependency(
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/** @type {Range} */ (expr.range),
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null,
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base,
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members,
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/** @type {string} */ (requireCall.argument.string),
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requireCall.ids,
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!parser.isStatementLevelExpression(expr)
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);
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dep.loc = /** @type {DependencyLocation} */ (expr.loc);
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dep.optional = Boolean(parser.scope.inTry);
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parser.state.module.addDependency(dep);
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return true;
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}
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if (members.length === 0) return;
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enableStructuredExports();
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const remainingMembers = members;
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checkNamespace(
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/** @type {StatementPath} */
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(parser.statementPath).length === 1 &&
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parser.isStatementLevelExpression(expr),
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remainingMembers,
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expr.right
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);
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const dep = new CommonJsExportsDependency(
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/** @type {Range} */ (expr.left.range),
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null,
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base,
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remainingMembers
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);
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dep.loc = /** @type {DependencyLocation} */ (expr.loc);
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parser.state.module.addDependency(dep);
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parser.walkExpression(expr.right);
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return true;
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};
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parser.hooks.assignMemberChain
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.for("exports")
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.tap("CommonJsExportsParserPlugin", (expr, members) =>
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handleAssignExport(expr, "exports", members)
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);
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parser.hooks.assignMemberChain
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.for("this")
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.tap("CommonJsExportsParserPlugin", (expr, members) => {
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if (!parser.scope.topLevelScope) return;
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return handleAssignExport(expr, "this", members);
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});
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parser.hooks.assignMemberChain
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.for("module")
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.tap("CommonJsExportsParserPlugin", (expr, members) => {
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if (members[0] !== "exports") return;
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return handleAssignExport(expr, "module.exports", members.slice(1));
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});
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parser.hooks.call
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.for("Object.defineProperty")
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.tap("CommonJsExportsParserPlugin", expression => {
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const expr = /** @type {CallExpression} */ (expression);
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if (!parser.isStatementLevelExpression(expr)) return;
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if (expr.arguments.length !== 3) return;
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if (expr.arguments[0].type === "SpreadElement") return;
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if (expr.arguments[1].type === "SpreadElement") return;
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if (expr.arguments[2].type === "SpreadElement") return;
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const exportsArg = parser.evaluateExpression(expr.arguments[0]);
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if (!exportsArg.isIdentifier()) return;
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if (
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exportsArg.identifier !== "exports" &&
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exportsArg.identifier !== "module.exports" &&
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(exportsArg.identifier !== "this" || !parser.scope.topLevelScope)
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) {
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return;
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}
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const propertyArg = parser.evaluateExpression(expr.arguments[1]);
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const property = propertyArg.asString();
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if (typeof property !== "string") return;
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enableStructuredExports();
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const descArg = expr.arguments[2];
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checkNamespace(
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/** @type {StatementPath} */
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(parser.statementPath).length === 1,
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[property],
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getValueOfPropertyDescription(descArg)
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);
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const dep = new CommonJsExportsDependency(
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/** @type {Range} */ (expr.range),
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/** @type {Range} */ (expr.arguments[2].range),
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`Object.defineProperty(${exportsArg.identifier})`,
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[property]
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);
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dep.loc = /** @type {DependencyLocation} */ (expr.loc);
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parser.state.module.addDependency(dep);
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parser.walkExpression(expr.arguments[2]);
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return true;
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});
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// Self reference //
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/**
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* @param {Expression | Super} expr expression
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* @param {CommonJSDependencyBaseKeywords} base commonjs base keywords
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* @param {string[]} members members of the export
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* @param {CallExpression=} call call expression
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* @returns {boolean | void} true, when the expression was handled
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*/
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const handleAccessExport = (expr, base, members, call) => {
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if (HarmonyExports.isEnabled(parser.state)) return;
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if (members.length === 0) {
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bailout(
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`${base} is used directly at ${formatLocation(
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/** @type {DependencyLocation} */ (expr.loc)
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)}`
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);
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}
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if (call && members.length === 1) {
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bailoutHint(
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`${base}${propertyAccess(
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members
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)}(...) prevents optimization as ${base} is passed as call context at ${formatLocation(
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/** @type {DependencyLocation} */ (expr.loc)
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)}`
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);
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}
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const dep = new CommonJsSelfReferenceDependency(
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/** @type {Range} */ (expr.range),
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base,
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members,
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Boolean(call)
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);
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dep.loc = /** @type {DependencyLocation} */ (expr.loc);
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parser.state.module.addDependency(dep);
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if (call) {
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parser.walkExpressions(call.arguments);
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}
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return true;
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};
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parser.hooks.callMemberChain
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.for("exports")
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.tap("CommonJsExportsParserPlugin", (expr, members) =>
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handleAccessExport(expr.callee, "exports", members, expr)
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);
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parser.hooks.expressionMemberChain
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.for("exports")
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.tap("CommonJsExportsParserPlugin", (expr, members) =>
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handleAccessExport(expr, "exports", members)
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);
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parser.hooks.expression
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.for("exports")
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.tap("CommonJsExportsParserPlugin", expr =>
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handleAccessExport(expr, "exports", [])
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);
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parser.hooks.callMemberChain
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.for("module")
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.tap("CommonJsExportsParserPlugin", (expr, members) => {
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if (members[0] !== "exports") return;
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return handleAccessExport(
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expr.callee,
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"module.exports",
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members.slice(1),
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expr
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);
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});
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parser.hooks.expressionMemberChain
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.for("module")
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.tap("CommonJsExportsParserPlugin", (expr, members) => {
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if (members[0] !== "exports") return;
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return handleAccessExport(expr, "module.exports", members.slice(1));
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});
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parser.hooks.expression
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.for("module.exports")
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.tap("CommonJsExportsParserPlugin", expr =>
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handleAccessExport(expr, "module.exports", [])
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);
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parser.hooks.callMemberChain
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.for("this")
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.tap("CommonJsExportsParserPlugin", (expr, members) => {
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if (!parser.scope.topLevelScope) return;
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return handleAccessExport(expr.callee, "this", members, expr);
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});
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parser.hooks.expressionMemberChain
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.for("this")
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.tap("CommonJsExportsParserPlugin", (expr, members) => {
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if (!parser.scope.topLevelScope) return;
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return handleAccessExport(expr, "this", members);
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});
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parser.hooks.expression
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.for("this")
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.tap("CommonJsExportsParserPlugin", expr => {
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if (!parser.scope.topLevelScope) return;
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return handleAccessExport(expr, "this", []);
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});
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// Bailouts //
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parser.hooks.expression.for("module").tap("CommonJsPlugin", expr => {
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bailout();
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const isHarmony = HarmonyExports.isEnabled(parser.state);
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const dep = new ModuleDecoratorDependency(
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isHarmony
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? RuntimeGlobals.harmonyModuleDecorator
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: RuntimeGlobals.nodeModuleDecorator,
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!isHarmony
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);
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dep.loc = /** @type {DependencyLocation} */ (expr.loc);
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parser.state.module.addDependency(dep);
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return true;
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});
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}
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}
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module.exports = CommonJsExportsParserPlugin;
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