ix/src/asynciterable/repeatvalue.ts

The Interactive Extensions for JavaScript

import { AsyncIterableX } from './asynciterablex.js';
import { throwIfAborted } from '../aborterror.js';

/** @ignore */
export class RepeatValueAsyncIterable<TSource> extends AsyncIterableX<TSource> {
  private _value: TSource;
  private _count: number;

  constructor(value: TSource, count: number) {
    super();
    this._value = value;
    this._count = count;
  }

  async *[Symbol.asyncIterator](signal?: AbortSignal) {
    if (this._count === -1) {
      while (1) {
        throwIfAborted(signal);
        yield this._value;
      }
    } else {
      for (let i = 0; i < this._count; i++) {
        throwIfAborted(signal);
        yield this._value;
      }
    }
  }
}

/**
 * Repeats a given value for the specified number of times as an async-iterable.
 *
 * @template TSource The type of element to repeat.
 * @param {TSource} value The value to repeat as an async-iterable.
 * @param {number} [count=-1] The number of times to repeat the value, infinite if not specified.
 * @returns {AsyncIterableX<TSource>} An async-iterable with a single item that is repeated over the specified times.
 */
export function repeatValue<TSource>(value: TSource, count = -1): AsyncIterableX<TSource> {
  return new RepeatValueAsyncIterable<TSource>(value, count);
}