Method popFront

data_structures/deque.ts:302–310

* Remove and return the front element, or `undefined` if the deque is empty. * * @example Popping from the front * ```ts * import { Deque } from "@std/data-structures/deque"; * import { assertEquals } from "@std/assert"; * * const deque = new Deque([1, 2, 3]); * assertEquals(

()

   * @returns The front element, or `undefined` if empty.
   */
  popFront(): T | undefined {
    if (this.#length === 0) return undefined;
    const value = this.#buffer[this.#head];
    this.#buffer[this.#head] = undefined;
    this.#head = (this.#head + 1) & this.#mask;
    this.#length--;
    this.#maybeShrink();
    return value;
  }

  /**
   * Remove and return the first element matching the predicate, scanning from