cancellable-promise.js

export const cancellablePromise = promise => {
  let isCanceled = false;

  const wrappedPromise = new Promise((resolve, reject) => {
    promise.then(
      value => (isCanceled ? reject({ isCanceled, value }) : resolve(value)),
      error => reject({ isCanceled, error }),
    );
  });

  return {
    promise: wrappedPromise,
    cancel: () => (isCanceled = true),
  };
};