xterm/src/common/TypedArrayUtils.ts

Full xterm terminal, in your browser

/**
 * Copyright (c) 2018 The xterm.js authors. All rights reserved.
 * @license MIT
 */

export type TypedArray = Uint8Array | Uint16Array | Uint32Array | Uint8ClampedArray
  | Int8Array | Int16Array | Int32Array
  | Float32Array | Float64Array;


/**
 * polyfill for TypedArray.fill
 * This is needed to support .fill in all safari versions and IE 11.
 */
export function fill<T extends TypedArray>(array: T, value: number, start?: number, end?: number): T {
  // all modern engines that support .fill
  if (array.fill) {
    return array.fill(value, start, end) as T;
  }
  return fillFallback(array, value, start, end);
}

export function fillFallback<T extends TypedArray>(array: T, value: number, start: number = 0, end: number = array.length): T {
  // safari and IE 11
  // since IE 11 does not support Array.prototype.fill either
  // we cannot use the suggested polyfill from MDN
  // instead we simply fall back to looping
  if (start >= array.length) {
    return array;
  }
  start = (array.length + start) % array.length;
  if (end >= array.length) {
    end = array.length;
  } else {
    end = (array.length + end) % array.length;
  }
  for (let i = start; i < end; ++i) {
    array[i] = value;
  }
  return array;
}

/**
 * Concat two typed arrays `a` and `b`.
 * Returns a new typed array.
 */
export function concat<T extends TypedArray>(a: T, b: T): T {
  const result = new (a.constructor as any)(a.length + b.length);
  result.set(a);
  result.set(b, a.length);
  return result;
}