open-browser-webpack4-plugin/index.js

Opens a new browser tab when Webpack loads. Very useful if you're lazy and don't want to force yourself to open a new tab when Webpack is ready to play!

var open = require("open");

/**
 * Creates a function that is restricted to invoking func once.
 * Repeat calls to the function return the value of the first invocation.
 * The func is invoked with the this binding and arguments of the created function.
 * @param {Function} function The function to restrict.
 * @returns {Function} Returns the new restricted function.
 */
function once(fn) {
  var called = false;
  return function() {
    if (!called) {
      called = true;
      fn.apply(this, arguments);
    }
  };
}

/**
 * Opens the browser the first time if there's no compilation errors.
 * @param {Object} options Options object.
 * @param {String} [options.url] Url to open in browser.
 * @param {Number} [options.delay] If no delay (in ms) is specified, the browser will be started immediately.
 * @param {String} [options.browser] Browser to use. If not available, use default browser.
 * @param {Boolean} [options.ignoreErrors] Ignore webpack errors.
 * @constructor
 */
function OpenBrowserPlugin(options) {
  options || (options = {});
  this.url = options.url || "http://localhost:8080";
  this.delay = options.delay || 0;
  this.browser = options.browser;
  this.ignoreErrors = options.ignoreErrors;
}

OpenBrowserPlugin.prototype.apply = function(compiler) {
  var isWatching = false;
  var url = this.url;
  var delay = this.delay;
  var browser = this.browser;
  var ignoreErrors = this.ignoreErrors;
  var executeOpen = once(function() {
    setTimeout(function() {
      open(url, browser, function(err) {
        if (err) throw err;
      });
    }, delay);
  });

  if (compiler.hooks) {
    compiler.hooks.watchRun.tap("watch-run", function checkWatchingMode() {
      isWatching = true;
    });

    compiler.hooks.done.tap("done", function doneCallback(stats) {
      if (isWatching && (!stats.hasErrors() || ignoreErrors)) {
        executeOpen();
      }
    });
  } else {
    compiler.plugin("watch-run", function checkWatchingMode(watching, done) {
      isWatching = true;
      done();
    });

    compiler.plugin("done", function doneCallback(stats) {
      if (isWatching && (!stats.hasErrors() || ignoreErrors)) {
        executeOpen();
      }
    });
  }
};

module.exports = OpenBrowserPlugin;