source: frontend/node_modules/webpack/lib/javascript/StartupHelpers.js

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

"use strict";

const RuntimeGlobals = require("../RuntimeGlobals");
const Template = require("../Template");
const { isSubset } = require("../util/SetHelpers");
const { getAllChunks } = require("./ChunkHelpers");

/** @typedef {import("../util/Hash")} Hash */
/** @typedef {import("../Chunk")} Chunk */
/** @typedef {import("../Chunk").ChunkId} ChunkId */
/** @typedef {import("../ChunkGraph")} ChunkGraph */
/** @typedef {import("../ChunkGraph").ModuleId} ModuleId */
/** @typedef {import("../Entrypoint")} Entrypoint */
/** @typedef {import("../ChunkGraph").EntryModuleWithChunkGroup} EntryModuleWithChunkGroup */
/** @typedef {import("../RuntimeTemplate")} RuntimeTemplate */

const EXPORT_PREFIX = `var ${RuntimeGlobals.exports} = `;

/** @typedef {Set<Chunk>} Chunks */
/** @typedef {ModuleId[]} ModuleIds */

/**
 * Returns runtime code.
 * @param {ChunkGraph} chunkGraph chunkGraph
 * @param {RuntimeTemplate} runtimeTemplate runtimeTemplate
 * @param {EntryModuleWithChunkGroup[]} entries entries
 * @param {Chunk} chunk chunk
 * @param {boolean} passive true: passive startup with on chunks loaded
 * @returns {string} runtime code
 */
module.exports.generateEntryStartup = (
        chunkGraph,
        runtimeTemplate,
        entries,
        chunk,
        passive
) => {
        /** @type {string[]} */
        const runtime = [
                `var __webpack_exec__ = ${runtimeTemplate.returningFunction(
                        `${RuntimeGlobals.require}(${RuntimeGlobals.entryModuleId} = moduleId)`,
                        "moduleId"
                )}`
        ];

        /**
         * Returns fn to execute.
         * @param {ModuleId} id id
         * @returns {string} fn to execute
         */
        const runModule = (id) => `__webpack_exec__(${JSON.stringify(id)})`;
        /**
         * Output combination.
         * @param {Chunks} chunks chunks
         * @param {ModuleIds} moduleIds module ids
         * @param {boolean=} final true when final, otherwise false
         */
        const outputCombination = (chunks, moduleIds, final) => {
                if (chunks.size === 0) {
                        runtime.push(
                                `${final ? EXPORT_PREFIX : ""}(${moduleIds.map(runModule).join(", ")});`
                        );
                } else {
                        const fn = runtimeTemplate.returningFunction(
                                moduleIds.map(runModule).join(", ")
                        );
                        runtime.push(
                                `${final && !passive ? EXPORT_PREFIX : ""}${
                                        passive
                                                ? RuntimeGlobals.onChunksLoaded
                                                : RuntimeGlobals.startupEntrypoint
                                }(0, ${JSON.stringify(Array.from(chunks, (c) => c.id))}, ${fn});`
                        );
                        if (final && passive) {
                                runtime.push(`${EXPORT_PREFIX}${RuntimeGlobals.onChunksLoaded}();`);
                        }
                }
        };

        /** @type {Chunks | undefined} */
        let currentChunks;
        /** @type {ModuleIds | undefined} */
        let currentModuleIds;

        for (const [module, entrypoint] of entries) {
                if (!chunkGraph.getModuleSourceTypes(module).has("javascript")) {
                        continue;
                }
                const runtimeChunk =
                        /** @type {Entrypoint} */
                        (entrypoint).getRuntimeChunk();
                const moduleId = /** @type {ModuleId} */ (chunkGraph.getModuleId(module));
                const chunks = getAllChunks(
                        /** @type {Entrypoint} */
                        (entrypoint),
                        chunk,
                        runtimeChunk
                );
                if (
                        currentChunks &&
                        currentChunks.size === chunks.size &&
                        isSubset(currentChunks, chunks)
                ) {
                        /** @type {ModuleIds} */
                        (currentModuleIds).push(moduleId);
                } else {
                        if (currentChunks) {
                                outputCombination(
                                        currentChunks,
                                        /** @type {ModuleIds} */ (currentModuleIds)
                                );
                        }
                        currentChunks = chunks;
                        currentModuleIds = [moduleId];
                }
        }

        // output current modules with export prefix
        if (currentChunks) {
                outputCombination(
                        currentChunks,
                        /** @type {ModuleIds} */
                        (currentModuleIds),
                        true
                );
        }
        runtime.push("");
        return Template.asString(runtime);
};

/**
 * Returns initially fulfilled chunk ids.
 * @param {Chunk} chunk the chunk
 * @param {ChunkGraph} chunkGraph the chunk graph
 * @param {(chunk: Chunk, chunkGraph: ChunkGraph) => boolean} filterFn filter function
 * @returns {Set<ChunkId>} initially fulfilled chunk ids
 */
module.exports.getInitialChunkIds = (chunk, chunkGraph, filterFn) => {
        /** @type {Set<ChunkId>} */
        const initialChunkIds = new Set(chunk.ids);
        for (const c of chunk.getAllInitialChunks()) {
                if (c === chunk || filterFn(c, chunkGraph)) continue;
                for (const id of /** @type {ChunkId[]} */ (c.ids)) {
                        initialChunkIds.add(id);
                }
        }
        return initialChunkIds;
};

/**
 * Processes the provided hash.
 * @param {Hash} hash the hash to update
 * @param {ChunkGraph} chunkGraph chunkGraph
 * @param {EntryModuleWithChunkGroup[]} entries entries
 * @param {Chunk} chunk chunk
 * @returns {void}
 */
module.exports.updateHashForEntryStartup = (
        hash,
        chunkGraph,
        entries,
        chunk
) => {
        for (const [module, entrypoint] of entries) {
                const runtimeChunk =
                        /** @type {Entrypoint} */
                        (entrypoint).getRuntimeChunk();
                const moduleId = chunkGraph.getModuleId(module);
                hash.update(`${moduleId}`);
                for (const c of getAllChunks(
                        /** @type {Entrypoint} */ (entrypoint),
                        chunk,
                        /** @type {Chunk} */ (runtimeChunk)
                )) {
                        hash.update(`${c.id}`);
                }
        }
};