playwright/packages/playwright-core/src/server/electron/loader.ts

/**
 * Copyright (c) Microsoft Corporation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

const { app } = require('electron');
const fs = require('fs');
const path = require('path');
const { chromiumSwitches } = require('../chromium/chromiumSwitches');

// Command line is like:
// [Electron, loader.js, --inspect=0, --remote-debugging-port=0, options.cwd, app.js, ...args]
const appPath = path.resolve(process.argv[4], process.argv[5]);
process.argv.splice(2, 4);
process.argv[1] = appPath;
// Now it is like
// [Electron, app.js, ...args]

for (const arg of chromiumSwitches) {
  const match = arg.match(/--([^=]*)=?(.*)/)!;
  app.commandLine.appendSwitch(match[1], match[2]);
}

// Defer ready event.
const originalWhenReady = app.whenReady();
const originalEmit = app.emit.bind(app);
let readyEventArgs: any[];
app.emit = (event: string | symbol, ...args: any[]): boolean => {
  if (event === 'ready') {
    readyEventArgs = args;
    return app.listenerCount('ready') > 0;
  }
  return originalEmit(event, ...args);
};

app.getAppPath = () => {
  if (fs.statSync(appPath).isFile())
    return path.dirname(appPath);
  return appPath;
};

let isReady = false;
let whenReadyCallback: (event: any) => any;
const whenReadyPromise = new Promise<void>(f => whenReadyCallback = f);
app.isReady = () => isReady;
app.whenReady = () => whenReadyPromise;

require(appPath);

(globalThis as any).__playwright_run = async () => {
  // Wait for app to be ready to avoid browser initialization races.
  const event = await originalWhenReady;
  isReady = true;
  whenReadyCallback(event);
  originalEmit('ready', ...readyEventArgs);
};