@monaco-editor/loader/lib/es/utils/makeCancelable.js

the library aims to setup monaco editor into your browser

// The source (has been changed) is https://github.com/facebook/react/issues/5465#issuecomment-157888325
var CANCELATION_MESSAGE = {
  type: 'cancelation',
  msg: 'operation is manually canceled'
};

function makeCancelable(promise) {
  var hasCanceled_ = false;
  var wrappedPromise = new Promise(function (resolve, reject) {
    promise.then(function (val) {
      return hasCanceled_ ? reject(CANCELATION_MESSAGE) : resolve(val);
    });
    promise["catch"](reject);
  });
  return wrappedPromise.cancel = function () {
    return hasCanceled_ = true;
  }, wrappedPromise;
}

export default makeCancelable;
export { CANCELATION_MESSAGE };