discourse/app/assets/javascripts/mini-loader.js

// Used by pretty-text in MiniRacer context

let define, requirejs;

(function () {
  let JS_MODULES = {};

  let registry = {};
  let seen = {};
  let FAILED = false;

  let uuid = 0;

  function tryFinally(tryable, finalizer) {
    try {
      return tryable();
    } finally {
      finalizer();
    }
  }

  function unsupportedModule(length) {
    throw new Error(
      "an unsupported module was defined, expected `define(name, deps, module)` instead got: `" +
        length +
        "` arguments to define`"
    );
  }

  let defaultDeps = ["require", "exports", "module"];

  function Module(name, deps, callback, exports) {
    this.id = uuid++;
    this.name = name;
    this.deps = !deps.length && callback.length ? defaultDeps : deps;
    this.exports = exports || {};
    this.callback = callback;
    this.state = undefined;
    this._require = undefined;
  }

  Module.prototype.makeRequire = function () {
    if (this._require) {
      return this._require;
    }
    this._require = (dep) => {
      return requirejs(resolve(dep, this.name));
    };
    this._require.has = (dep) => {
      const moduleName = resolve(dep, this.name);
      return require.has(moduleName);
    };
    return this._require;
  };

  define = function (name, deps, callback) {
    if (arguments.length < 2) {
      unsupportedModule(arguments.length);
    }

    if (!Array.isArray(deps)) {
      callback = deps;
      deps = [];
    }

    registry[name] = new Module(name, deps, callback);
  };

  // we don't support all of AMD
  // define.amd = {};
  // we will support petals...
  define.petal = {};

  function Alias(path) {
    this.name = path;
  }

  define.alias = function (path) {
    return new Alias(path);
  };

  function reify(mod, name, rseen) {
    let deps = mod.deps;
    let length = deps.length;
    let reified = new Array(length);
    let dep;
    // TODO: new Module
    // TODO: seen refactor
    let module = {};

    for (let i = 0, l = length; i < l; i++) {
      dep = deps[i];
      if (dep === "exports") {
        module.exports = reified[i] = rseen;
      } else if (dep === "require") {
        reified[i] = mod.makeRequire();
      } else if (dep === "module") {
        mod.exports = rseen;
        module = reified[i] = mod;
      } else {
        reified[i] = requireFrom(resolve(dep, name), name);
      }
    }

    return {
      deps: reified,
      module,
    };
  }

  function requireFrom(name, origin) {
    let mod = JS_MODULES[name] || registry[name];

    if (!mod) {
      name = name + "/index";
      mod = registry[name];
    }

    if (!mod) {
      throw new Error(
        "Could not find module `" + name + "` imported from `" + origin + "`"
      );
    }
    return requirejs(name);
  }

  function missingModule(name) {
    throw new Error("Could not find module " + name);
  }

  requirejs = require = function (name) {
    if (JS_MODULES[name]) {
      return JS_MODULES[name];
    }

    let mod = registry[name];

    if (mod && mod.callback instanceof Alias) {
      mod = registry[mod.callback.name];
    }

    if (!mod) {
      name = name + "/index";
      mod = registry[name];
    }

    if (!mod) {
      missingModule(name);
    }

    if (mod.state !== FAILED && seen.hasOwnProperty(name)) {
      return seen[name];
    }

    let reified;
    let module;
    let loaded = false;

    seen[name] = {}; // placeholder for run-time cycles

    tryFinally(
      function () {
        reified = reify(mod, name, seen[name]);
        module = mod.callback.apply(this, reified.deps);
        loaded = true;
      },
      function () {
        if (!loaded) {
          mod.state = FAILED;
        }
      }
    );

    let obj;
    if (module === undefined && reified.module.exports) {
      obj = reified.module.exports;
    } else {
      obj = seen[name] = module;
    }

    if (
      obj !== null &&
      (typeof obj === "object" || typeof obj === "function") &&
      obj["default"] === undefined
    ) {
      obj["default"] = obj;
    }

    return (seen[name] = obj);
  };
  window.requireModule = requirejs;

  function resolve(child, name) {
    if (child.charAt(0) !== ".") {
      return child;
    }

    let parts = child.split("/");
    let nameParts = name.split("/");
    let parentBase = nameParts.slice(0, -1);

    for (let i = 0, l = parts.length; i < l; i++) {
      let part = parts[i];

      if (part === "..") {
        if (parentBase.length === 0) {
          throw new Error("Cannot access parent module of root");
        }
        parentBase.pop();
      } else if (part === ".") {
        continue;
      } else {
        parentBase.push(part);
      }
    }

    return parentBase.join("/");
  }

  requirejs.entries = requirejs._eak_seen = registry;
  requirejs.clear = function () {
    requirejs.entries = requirejs._eak_seen = registry = {};
    seen = {};
  };
  require.has = function (moduleName) {
    return (
      Boolean(registry[moduleName]) || Boolean(registry[moduleName + "/index"])
    );
  };

  globalThis.define = define;
  globalThis.require = require;
})();