Method unshift

lib/internal/streams/iter/ringbuffer.js:46–53

* Prepend an item to the head. O(1) amortized.

(item)

   * Prepend an item to the head. O(1) amortized.
   */
  unshift(item) {
    if (this.#size > this.#mask) {
      this.#grow();
    }
    this.#head = (this.#head - 1 + this.#mask + 1) & this.#mask;
    this.#backing[this.#head] = item;
    this.#size++;
  }

  /**
   * Remove and return the item at the head. O(1).