@primer/react/lib/polyfills/eventListenerSignal.js

An implementation of GitHub's Primer Design System using React

'use strict';

/*

This file polyfills the following: https://github.com/whatwg/dom/issues/911
Once all targeted browsers support this DOM feature, this polyfill can be deleted.

This allows users to pass an AbortSignal to a call to addEventListener as part of the
AddEventListenerOptions object. When the signal is aborted, the event listener is
removed.

*/

let signalSupported = false;
function noop() {}
try {
  const options = Object.create({}, {
    signal: {
      get() {
        signalSupported = true;
      }
    }
  });
  window.addEventListener('test', noop, options);
  window.removeEventListener('test', noop, options);
} catch (e) {
  /* */
}
function featureSupported() {
  return signalSupported;
}
function monkeyPatch() {
  if (typeof window === 'undefined') {
    return;
  }
  const originalAddEventListener = EventTarget.prototype.addEventListener;
  EventTarget.prototype.addEventListener = function (name, originalCallback, optionsOrCapture) {
    if (typeof optionsOrCapture === 'object' && 'signal' in optionsOrCapture && optionsOrCapture.signal instanceof AbortSignal) {
      originalAddEventListener.call(optionsOrCapture.signal, 'abort', () => {
        this.removeEventListener(name, originalCallback, optionsOrCapture);
      });
    }
    return originalAddEventListener.call(this, name, originalCallback, optionsOrCapture);
  };
}
function polyfill() {
  if (!featureSupported()) {
    monkeyPatch();
    signalSupported = true;
  }
}

exports.polyfill = polyfill;