ruffle/web/packages/core/src/load-ruffle.ts

/* eslint @typescript-eslint/no-explicit-any: "off" */

/**
 * Conditional ruffle loader
 */

import init, { Ruffle } from "../pkg/ruffle_web";
import { setPolyfillsOnLoad } from "./js-polyfills";

/**
 * Load ruffle from an automatically-detected location.
 *
 * This function returns a new instance of Ruffle and downloads it every time.
 * You should not use it directly; this module will memoize the resource
 * download.
 *
 * @returns A ruffle constructor that may be used to create new Ruffle
 * instances.
 */
async function fetchRuffle(): Promise<{ new (...args: any[]): Ruffle }> {
    // Apply some pure JavaScript polyfills to prevent conflicts with external
    // libraries, if needed.
    setPolyfillsOnLoad();

    let isExtension = true;

    try {
        // If ruffleRuntimePath is defined then we are executing inside the extension
        // closure. In that case, we configure our local Webpack instance.
        __webpack_public_path__ = ruffleRuntimePath + "dist/";
    } catch (e) {
        // Checking an undefined closure variable usually throws ReferenceError,
        // so we need to catch it here and continue onward.
        if (!(e instanceof ReferenceError)) {
            throw e;
        }
        isExtension = false;
    }

    // We currently assume that if we are not executing inside the extension,
    // then we can use webpack to get Ruffle.

    try {
        // wasm files are set to use file-loader,
        // so this package will resolve to the URL of the wasm file.
        const ruffleWasm = await import(
            /* webpackMode: "eager" */
            "../pkg/ruffle_web_bg.wasm"
        );
        await init(ruffleWasm.default);
    } catch (e) {
        e.ruffleIsExtension = isExtension;
        throw e;
    }

    return Ruffle;
}

let lastLoaded: Promise<{ new (...args: any[]): Ruffle }> | null = null;

/**
 * Obtain an instance of `Ruffle`.
 *
 * This function returns a promise which yields `Ruffle` asynchronously.
 *
 * @returns A ruffle constructor that may be used to create new Ruffle
 * instances.
 */
export function loadRuffle(): Promise<{ new (...args: any[]): Ruffle }> {
    if (lastLoaded == null) {
        lastLoaded = fetchRuffle();
    }

    return lastLoaded;
}