abortcontroller-polyfill/src/utils.js

Polyfill/ponyfill for the AbortController DOM API + optional patching of fetch (stub that calls catch, doesn't actually abort request).

export function polyfillNeeded(self) {
  if (self.__FORCE_INSTALL_ABORTCONTROLLER_POLYFILL) {
    console.log('__FORCE_INSTALL_ABORTCONTROLLER_POLYFILL=true is set, will force install polyfill');
    return true;
  }

  // Note that the "unfetch" minimal fetch polyfill defines fetch() without
  // defining window.Request, and this polyfill need to work on top of unfetch
  // so the below feature detection needs the !self.AbortController part.
  // The Request.prototype check is also needed because Safari versions 11.1.2
  // up to and including 12.1.x has a window.AbortController present but still
  // does NOT correctly implement abortable fetch:
  // https://bugs.webkit.org/show_bug.cgi?id=174980#c2
  return (
    (typeof self.Request === 'function' && !self.Request.prototype.hasOwnProperty('signal')) || !self.AbortController
  );
}

export function signalPolyfillNeeded(self) {
  if (self.__FORCE_INSTALL_ABORTCONTROLLER_POLYFILL) {
    console.log('__FORCE_INSTALL_ABORTCONTROLLER_POLYFILL=true is set, will force install polyfill');
    return true;
  }

  return (
    !!self.AbortController &&
    typeof self.AbortSignal === 'function' &&
    !self.AbortSignal.prototype.hasOwnProperty('reason')
  );
}