source: frontend/node_modules/webpack/lib/runtime/LoadScriptRuntimeModule.js

/*
        MIT License http://www.opensource.org/licenses/mit-license.php
*/

"use strict";

const { SyncWaterfallHook } = require("tapable");
const Compilation = require("../Compilation");
const RuntimeGlobals = require("../RuntimeGlobals");
const Template = require("../Template");
const HelperRuntimeModule = require("./HelperRuntimeModule");

/** @typedef {import("../Chunk")} Chunk */

/**
 * @typedef {object} LoadScriptCompilationHooks
 * @property {SyncWaterfallHook<[string, Chunk]>} createScript
 */

/** @type {WeakMap<Compilation, LoadScriptCompilationHooks>} */
const compilationHooksMap = new WeakMap();

class LoadScriptRuntimeModule extends HelperRuntimeModule {
        /**
         * @param {Compilation} compilation the compilation
         * @returns {LoadScriptCompilationHooks} hooks
         */
        static getCompilationHooks(compilation) {
                if (!(compilation instanceof Compilation)) {
                        throw new TypeError(
                                "The 'compilation' argument must be an instance of Compilation"
                        );
                }
                let hooks = compilationHooksMap.get(compilation);
                if (hooks === undefined) {
                        hooks = {
                                createScript: new SyncWaterfallHook(["source", "chunk"])
                        };
                        compilationHooksMap.set(compilation, hooks);
                }
                return hooks;
        }

        /**
         * @param {boolean=} withCreateScriptUrl use create script url for trusted types
         * @param {boolean=} withFetchPriority use `fetchPriority` attribute
         */
        constructor(withCreateScriptUrl, withFetchPriority) {
                super("load script");
                /** @type {boolean | undefined} */
                this._withCreateScriptUrl = withCreateScriptUrl;
                /** @type {boolean | undefined} */
                this._withFetchPriority = withFetchPriority;
        }

        /**
         * Generates runtime code for this runtime module.
         * @returns {string | null} runtime code
         */
        generate() {
                const compilation = /** @type {Compilation} */ (this.compilation);
                const { runtimeTemplate, outputOptions } = compilation;
                const {
                        scriptType,
                        chunkLoadTimeout: loadTimeout,
                        crossOriginLoading,
                        uniqueName,
                        charset
                } = outputOptions;
                const fn = RuntimeGlobals.loadScript;

                const { createScript } =
                        LoadScriptRuntimeModule.getCompilationHooks(compilation);

                const code = Template.asString([
                        "script = document.createElement('script');",
                        scriptType ? `script.type = ${JSON.stringify(scriptType)};` : "",
                        charset ? "script.charset = 'utf-8';" : "",
                        `if (${RuntimeGlobals.scriptNonce}) {`,
                        Template.indent(
                                `script.setAttribute("nonce", ${RuntimeGlobals.scriptNonce});`
                        ),
                        "}",
                        uniqueName
                                ? 'script.setAttribute("data-webpack", dataWebpackPrefix + key);'
                                : "",
                        this._withFetchPriority
                                ? Template.asString([
                                                "if(fetchPriority) {",
                                                Template.indent(
                                                        'script.setAttribute("fetchpriority", fetchPriority);'
                                                ),
                                                "}"
                                        ])
                                : "",
                        `script.src = ${
                                this._withCreateScriptUrl
                                        ? `${RuntimeGlobals.createScriptUrl}(url)`
                                        : "url"
                        };`,
                        crossOriginLoading
                                ? crossOriginLoading === "use-credentials"
                                        ? 'script.crossOrigin = "use-credentials";'
                                        : Template.asString([
                                                        "if (script.src.indexOf(window.location.origin + '/') !== 0) {",
                                                        Template.indent(
                                                                `script.crossOrigin = ${JSON.stringify(crossOriginLoading)};`
                                                        ),
                                                        "}"
                                                ])
                                : ""
                ]);

                return Template.asString([
                        "var inProgress = {};",
                        uniqueName
                                ? `var dataWebpackPrefix = ${JSON.stringify(`${uniqueName}:`)};`
                                : "// data-webpack is not used as build has no uniqueName",
                        "// loadScript function to load a script via script tag",
                        `${fn} = ${runtimeTemplate.basicFunction(
                                `url, done, key, chunkId${
                                        this._withFetchPriority ? ", fetchPriority" : ""
                                }`,
                                [
                                        "if(inProgress[url]) { inProgress[url].push(done); return; }",
                                        "var script, needAttach;",
                                        "if(key !== undefined) {",
                                        Template.indent([
                                                'var scripts = document.getElementsByTagName("script");',
                                                "for(var i = 0; i < scripts.length; i++) {",
                                                Template.indent([
                                                        "var s = scripts[i];",
                                                        `if(s.getAttribute("src") == url${
                                                                uniqueName
                                                                        ? ' || s.getAttribute("data-webpack") == dataWebpackPrefix + key'
                                                                        : ""
                                                        }) { script = s; break; }`
                                                ]),
                                                "}"
                                        ]),
                                        "}",
                                        "if(!script) {",
                                        Template.indent([
                                                "needAttach = true;",
                                                createScript.call(code, /** @type {Chunk} */ (this.chunk))
                                        ]),
                                        "}",
                                        "inProgress[url] = [done];",
                                        `var onScriptComplete = ${runtimeTemplate.basicFunction(
                                                "prev, event",
                                                Template.asString([
                                                        "// avoid mem leaks in IE.",
                                                        "script.onerror = script.onload = null;",
                                                        "clearTimeout(timeout);",
                                                        "var doneFns = inProgress[url];",
                                                        "delete inProgress[url];",
                                                        "script.parentNode && script.parentNode.removeChild(script);",
                                                        `doneFns && doneFns.forEach(${runtimeTemplate.returningFunction(
                                                                "fn(event)",
                                                                "fn"
                                                        )});`,
                                                        "if(prev) return prev(event);"
                                                ])
                                        )}`,
                                        `var timeout = setTimeout(onScriptComplete.bind(null, undefined, { type: 'timeout', target: script }), ${loadTimeout});`,
                                        "script.onerror = onScriptComplete.bind(null, script.onerror);",
                                        "script.onload = onScriptComplete.bind(null, script.onload);",
                                        "needAttach && document.head.appendChild(script);"
                                ]
                        )};`
                ]);
        }
}

module.exports = LoadScriptRuntimeModule;