@jcoreio/abortable/index.mjs

memory-leak-proof function to wrap a promise to reject when a signal is aborted

export const newAbortError = () => new DOMException('This operation was aborted', 'AbortError');
const noop = () => {};
export function abortable(promise, signal) {
  if (!signal) return promise;
  return new Promise((resolve, reject) => {
    const cleanup = () => {
      const callbacks = {
        resolve,
        reject
      };
      // Prevent memory leaks.  If the input promise never resolves, then the handlers
      // below would retain this enclosing Promise's resolve and reject callbacks,
      // which would retain the enclosing Promise and anything waiting on it.
      // By replacing references to these callbacks, we enable the enclosing Promise to
      // be garbage collected
      resolve = noop;
      reject = noop;
      // Memory could also leak if the signal never aborts, unless we remove the abort
      // handler
      signal.removeEventListener('abort', onAbort);
      return callbacks;
    };
    const onAbort = () => cleanup().reject(newAbortError());
    promise.then(value => cleanup().resolve(value), error => cleanup().reject(error));
    if (signal.aborted) {
      reject(newAbortError());
    } else {
      signal.addEventListener('abort', onAbort);
    }
  });
}
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