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3 weeks ago
/*
MIT License http://www.opensource.org/licenses/mit-license.php
*/
"use strict";
const RuntimeGlobals = require("../RuntimeGlobals");
const Template = require("../Template");
const HelperRuntimeModule = require("./HelperRuntimeModule");
/** @typedef {import("../Compilation")} Compilation */
class CreateFakeNamespaceObjectRuntimeModule extends HelperRuntimeModule {
constructor() {
super("create fake namespace object");
}
/**
* @returns {string | null} runtime code
*/
generate() {
const compilation = /** @type {Compilation} */ (this.compilation);
const { runtimeTemplate } = compilation;
const fn = RuntimeGlobals.createFakeNamespaceObject;
return Template.asString([
`var getProto = Object.getPrototypeOf ? ${runtimeTemplate.returningFunction(
"Object.getPrototypeOf(obj)",
"obj"
)} : ${runtimeTemplate.returningFunction("obj.__proto__", "obj")};`,
"var leafPrototypes;",
"// create a fake namespace object",
"// mode & 1: value is a module id, require it",
"// mode & 2: merge all properties of value into the ns",
"// mode & 4: return value when already ns object",
"// mode & 16: return value when it's Promise-like",
"// mode & 8|1: behave like require",
// Note: must be a function (not arrow), because this is used in body!
`${fn} = function(value, mode) {`,
Template.indent([
"if(mode & 1) value = this(value);",
"if(mode & 8) return value;",
"if(typeof value === 'object' && value) {",
Template.indent([
"if((mode & 4) && value.__esModule) return value;",
"if((mode & 16) && typeof value.then === 'function') return value;"
]),
"}",
"var ns = Object.create(null);",
`${RuntimeGlobals.makeNamespaceObject}(ns);`,
"var def = {};",
"leafPrototypes = leafPrototypes || [null, getProto({}), getProto([]), getProto(getProto)];",
"for(var current = mode & 2 && value; typeof current == 'object' && !~leafPrototypes.indexOf(current); current = getProto(current)) {",
Template.indent([
`Object.getOwnPropertyNames(current).forEach(${runtimeTemplate.expressionFunction(
`def[key] = ${runtimeTemplate.returningFunction("value[key]", "")}`,
"key"
)});`
]),
"}",
`def['default'] = ${runtimeTemplate.returningFunction("value", "")};`,
`${RuntimeGlobals.definePropertyGetters}(ns, def);`,
"return ns;"
]),
"};"
]);
}
}
module.exports = CreateFakeNamespaceObjectRuntimeModule;