ix/src/asynciterable/every.ts

The Interactive Extensions for JavaScript

import { wrapWithAbort } from './operators/withabort.js';
import { throwIfAborted } from '../aborterror.js';
import { FindOptions } from './findoptions.js';

/**
 * Determines whether all elements of an async-iterable sequence satisfy a condition.
 *
 * @template T The type of the elements in the source sequence.
 * @param {AsyncIterable<T>} source An async-iterable sequence whose elements to apply the predicate to.
 * @param {FindOptions<T>} options The options for a predicate for filtering, thisArg for binding and AbortSignal for cancellation.
 * @returns {Promise<boolean>} An async-iterable sequence containing a single element determining whether all elements in the
 * source sequence pass the test in the specified predicate.
 */
export async function every<T>(
  source: AsyncIterable<T>,
  options: FindOptions<T>
): Promise<boolean> {
  const { ['signal']: signal, ['thisArg']: thisArg, ['predicate']: predicate } = options;
  throwIfAborted(signal);
  let i = 0;
  for await (const item of wrapWithAbort(source, signal)) {
    if (!(await predicate.call(thisArg, item, i++, signal))) {
      return false;
    }
  }
  return true;
}