source: imaps-frontend/node_modules/webpack/lib/node/ReadFileCompileAsyncWasmPlugin.js

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

"use strict";

const { WEBASSEMBLY_MODULE_TYPE_ASYNC } = require("../ModuleTypeConstants");
const RuntimeGlobals = require("../RuntimeGlobals");
const Template = require("../Template");
const AsyncWasmLoadingRuntimeModule = require("../wasm-async/AsyncWasmLoadingRuntimeModule");

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

/**
 * @typedef {object} ReadFileCompileAsyncWasmPluginOptions
 * @property {boolean} [import] use import?
 */

const PLUGIN_NAME = "ReadFileCompileAsyncWasmPlugin";

class ReadFileCompileAsyncWasmPlugin {
        /**
         * @param {ReadFileCompileAsyncWasmPluginOptions} [options] options object
         */
        constructor({ import: useImport = false } = {}) {
                this._import = useImport;
        }

        /**
         * Apply the plugin
         * @param {Compiler} compiler the compiler instance
         * @returns {void}
         */
        apply(compiler) {
                compiler.hooks.thisCompilation.tap(PLUGIN_NAME, compilation => {
                        const globalWasmLoading = compilation.outputOptions.wasmLoading;
                        /**
                         * @param {Chunk} chunk chunk
                         * @returns {boolean} true, if wasm loading is enabled for the chunk
                         */
                        const isEnabledForChunk = chunk => {
                                const options = chunk.getEntryOptions();
                                const wasmLoading =
                                        options && options.wasmLoading !== undefined
                                                ? options.wasmLoading
                                                : globalWasmLoading;
                                return wasmLoading === "async-node";
                        };

                        /**
                         * @param {string} path path to wasm file
                         * @returns {string} generated code to load the wasm file
                         */
                        const generateLoadBinaryCode = this._import
                                ? path =>
                                                Template.asString([
                                                        "Promise.all([import('fs'), import('url')]).then(([{ readFile }, { URL }]) => new Promise((resolve, reject) => {",
                                                        Template.indent([
                                                                `readFile(new URL(${path}, ${compilation.outputOptions.importMetaName}.url), (err, buffer) => {`,
                                                                Template.indent([
                                                                        "if (err) return reject(err);",
                                                                        "",
                                                                        "// Fake fetch response",
                                                                        "resolve({",
                                                                        Template.indent(["arrayBuffer() { return buffer; }"]),
                                                                        "});"
                                                                ]),
                                                                "});"
                                                        ]),
                                                        "}))"
                                                ])
                                : path =>
                                                Template.asString([
                                                        "new Promise(function (resolve, reject) {",
                                                        Template.indent([
                                                                "try {",
                                                                Template.indent([
                                                                        "var { readFile } = require('fs');",
                                                                        "var { join } = require('path');",
                                                                        "",
                                                                        `readFile(join(__dirname, ${path}), function(err, buffer){`,
                                                                        Template.indent([
                                                                                "if (err) return reject(err);",
                                                                                "",
                                                                                "// Fake fetch response",
                                                                                "resolve({",
                                                                                Template.indent(["arrayBuffer() { return buffer; }"]),
                                                                                "});"
                                                                        ]),
                                                                        "});"
                                                                ]),
                                                                "} catch (err) { reject(err); }"
                                                        ]),
                                                        "})"
                                                ]);

                        compilation.hooks.runtimeRequirementInTree
                                .for(RuntimeGlobals.instantiateWasm)
                                .tap(PLUGIN_NAME, (chunk, set, { chunkGraph }) => {
                                        if (!isEnabledForChunk(chunk)) return;
                                        if (
                                                !chunkGraph.hasModuleInGraph(
                                                        chunk,
                                                        m => m.type === WEBASSEMBLY_MODULE_TYPE_ASYNC
                                                )
                                        ) {
                                                return;
                                        }
                                        compilation.addRuntimeModule(
                                                chunk,
                                                new AsyncWasmLoadingRuntimeModule({
                                                        generateLoadBinaryCode,
                                                        supportsStreaming: false
                                                })
                                        );
                                });
                });
        }
}

module.exports = ReadFileCompileAsyncWasmPlugin;