source: frontend/node_modules/webpack/lib/dependencies/CommonJsExportsDependency.js

/*
        MIT License http://www.opensource.org/licenses/mit-license.php
        Author Tobias Koppers @sokra
*/

"use strict";

const InitFragment = require("../InitFragment");
const makeSerializable = require("../util/makeSerializable");
const { propertyAccess } = require("../util/property");
const { handleDependencyBase } = require("./CommonJsDependencyHelpers");
const NullDependency = require("./NullDependency");

/** @typedef {import("webpack-sources").ReplaceSource} ReplaceSource */
/** @typedef {import("../Dependency")} Dependency */
/** @typedef {import("../Dependency").ExportsSpec} ExportsSpec */
/** @typedef {import("../DependencyTemplate").DependencyTemplateContext} DependencyTemplateContext */
/** @typedef {import("../ModuleGraph")} ModuleGraph */
/** @typedef {import("../ExportsInfo").ExportInfoName} ExportInfoName */
/** @typedef {import("../javascript/JavascriptParser").Range} Range */
/** @typedef {import("../serialization/ObjectMiddleware").ObjectDeserializerContext} ObjectDeserializerContext */
/** @typedef {import("../serialization/ObjectMiddleware").ObjectSerializerContext} ObjectSerializerContext */
/** @typedef {import("./CommonJsDependencyHelpers").CommonJSDependencyBaseKeywords} CommonJSDependencyBaseKeywords */

const EMPTY_OBJECT = {};

class CommonJsExportsDependency extends NullDependency {
        /**
         * Creates an instance of CommonJsExportsDependency.
         * @param {Range} range range
         * @param {Range | null} valueRange value range
         * @param {CommonJSDependencyBaseKeywords} base base
         * @param {ExportInfoName[]} names names
         */
        constructor(range, valueRange, base, names) {
                super();
                this.range = range;
                this.valueRange = valueRange;
                this.base = base;
                this.names = names;
        }

        get type() {
                return "cjs exports";
        }

        /**
         * Returns the exported names
         * @param {ModuleGraph} moduleGraph module graph
         * @returns {ExportsSpec | undefined} export names
         */
        getExports(moduleGraph) {
                const name = this.names[0];
                return {
                        exports: [
                                {
                                        name,
                                        // we can't mangle names that are in an empty object
                                        // because one could access the prototype property
                                        // when export isn't set yet
                                        canMangle: !(name in EMPTY_OBJECT)
                                }
                        ],
                        dependencies: undefined
                };
        }

        /**
         * Serializes this instance into the provided serializer context.
         * @param {ObjectSerializerContext} context context
         */
        serialize(context) {
                const { write } = context;
                write(this.range);
                write(this.valueRange);
                write(this.base);
                write(this.names);
                super.serialize(context);
        }

        /**
         * Restores this instance from the provided deserializer context.
         * @param {ObjectDeserializerContext} context context
         */
        deserialize(context) {
                const { read } = context;
                this.range = read();
                this.valueRange = read();
                this.base = read();
                this.names = read();
                super.deserialize(context);
        }
}

makeSerializable(
        CommonJsExportsDependency,
        "webpack/lib/dependencies/CommonJsExportsDependency"
);

CommonJsExportsDependency.Template = class CommonJsExportsDependencyTemplate extends (
        NullDependency.Template
) {
        /**
         * Applies the plugin by registering its hooks on the compiler.
         * @param {Dependency} dependency the dependency for which the template should be applied
         * @param {ReplaceSource} source the current replace source which can be modified
         * @param {DependencyTemplateContext} templateContext the context object
         * @returns {void}
         */
        apply(
                dependency,
                source,
                { module, moduleGraph, initFragments, runtimeRequirements, runtime }
        ) {
                const dep = /** @type {CommonJsExportsDependency} */ (dependency);
                const used = moduleGraph
                        .getExportsInfo(module)
                        .getUsedName(dep.names, runtime);

                const [type, base] = handleDependencyBase(
                        dep.base,
                        module,
                        runtimeRequirements
                );

                switch (type) {
                        case "expression":
                                if (!used) {
                                        initFragments.push(
                                                new InitFragment(
                                                        "var __webpack_unused_export__;\n",
                                                        InitFragment.STAGE_CONSTANTS,
                                                        0,
                                                        "__webpack_unused_export__"
                                                )
                                        );
                                        source.replace(
                                                dep.range[0],
                                                dep.range[1] - 1,
                                                "__webpack_unused_export__"
                                        );
                                        return;
                                }
                                source.replace(
                                        dep.range[0],
                                        dep.range[1] - 1,
                                        `${base}${propertyAccess(used)}`
                                );
                                return;
                        case "Object.defineProperty":
                                if (!used) {
                                        initFragments.push(
                                                new InitFragment(
                                                        "var __webpack_unused_export__;\n",
                                                        InitFragment.STAGE_CONSTANTS,
                                                        0,
                                                        "__webpack_unused_export__"
                                                )
                                        );
                                        source.replace(
                                                dep.range[0],
                                                /** @type {Range} */ (dep.valueRange)[0] - 1,
                                                "__webpack_unused_export__ = ("
                                        );
                                        source.replace(
                                                /** @type {Range} */ (dep.valueRange)[1],
                                                dep.range[1] - 1,
                                                ")"
                                        );
                                        return;
                                }
                                source.replace(
                                        dep.range[0],
                                        /** @type {Range} */ (dep.valueRange)[0] - 1,
                                        `Object.defineProperty(${base}${propertyAccess(
                                                used.slice(0, -1)
                                        )}, ${JSON.stringify(used[used.length - 1])}, (`
                                );
                                source.replace(
                                        /** @type {Range} */ (dep.valueRange)[1],
                                        dep.range[1] - 1,
                                        "))"
                                );
                }
        }
};

module.exports = CommonJsExportsDependency;