openBrowser.js

/**
 * Copyright (c) 2015-present, Facebook, Inc.
 * All rights reserved.
 *
 * This source code is licensed under the BSD-style license found in the
 * LICENSE file in the root directory of this source tree. An additional grant
 * of patent rights can be found in the PATENTS file in the same directory.
 */

var execSync = require('child_process').execSync;
var opn = require('opn');

// https://github.com/sindresorhus/opn#app
var OSX_CHROME = 'google chrome';

function openBrowser(url) {
  // Attempt to honor this environment variable.
  // It is specific to the operating system.
  // See https://github.com/sindresorhus/opn#app for documentation.
  let browser = process.env.BROWSER;

  // Special case: BROWSER="none" will prevent opening completely.
  if (browser === 'none') {
    return false;
  }

  // If we're on OS X, the user hasn't specifically
  // requested a different browser, we can try opening
  // Chrome with AppleScript. This lets us reuse an
  // existing tab when possible instead of creating a new one.
  const shouldTryOpenChromeWithAppleScript = (
    process.platform === 'darwin' && (
      typeof browser !== 'string' ||
      browser === OSX_CHROME
    )
  );

  if (shouldTryOpenChromeWithAppleScript) {
    try {
      // Try our best to reuse existing tab
      // on OS X Google Chrome with AppleScript
      execSync('ps cax | grep "Google Chrome"');
      execSync(
        'osascript openChrome.applescript ' + url,
        {cwd: __dirname, stdio: 'ignore'}
      );
      return true;
    } catch (err) {
      // Ignore errors.
    }
  }

  // Another special case: on OS X, check if BROWSER has been set to "open".
  // In this case, instead of passing `open` to `opn` (which won't work),
  // just ignore it (thus ensuring the intended behavior, i.e. opening the system browser):
  // https://github.com/facebookincubator/create-react-app/pull/1690#issuecomment-283518768
  if (process.platform === 'darwin' && browser === 'open') {
    browser = undefined;
  }
  
  // Fallback to opn
  // (It will always open new tab)
  try {
    var options = {app: browser};
    opn(url, options).catch(() => {}); // Prevent `unhandledRejection` error.
    return true;
  } catch (err) {
    return false;
  }
}

module.exports = openBrowser;