init

马宇豪

2024-07-16 f591c27b57e2418c9495bc02ae8cfff84d35bc18

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/*
    MIT License http://www.opensource.org/licenses/mit-license.php
*/
 
"use strict";
 
const RuntimeGlobals = require("../RuntimeGlobals");
const Template = require("../Template");
const HelperRuntimeModule = require("./HelperRuntimeModule");
 
class CreateFakeNamespaceObjectRuntimeModule extends HelperRuntimeModule {
    constructor() {
        super("create fake namespace object");
    }
 
    /**
     * @returns {string} runtime code
     */
    generate() {
        const { runtimeTemplate } = this.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;