@dfinity/agent/src/utils/buffer.ts

JavaScript and TypeScript library to interact with the Internet Computer

/**
 * Returns a true Uint8Array from an ArrayBufferLike object.
 * @param bufLike a buffer-like object
 * @returns Uint8Array
 */
export function uint8FromBufLike(
  bufLike:
    | ArrayBuffer
    | Uint8Array
    | DataView
    | ArrayBufferView
    | ArrayBufferLike
    | [number]
    | number[]
    | { buffer: ArrayBuffer },
): Uint8Array {
  if (!bufLike) {
    throw new Error('Input cannot be null or undefined');
  }

  if (bufLike instanceof Uint8Array) {
    return bufLike;
  }
  if (bufLike instanceof ArrayBuffer) {
    return new Uint8Array(bufLike);
  }
  if (Array.isArray(bufLike)) {
    return new Uint8Array(bufLike);
  }
  if ('buffer' in bufLike) {
    return uint8FromBufLike(bufLike.buffer);
  }
  return new Uint8Array(bufLike);
}

/**
 * Returns a true ArrayBuffer from a Uint8Array, as Uint8Array.buffer is unsafe.
 * @param {Uint8Array} arr Uint8Array to convert
 * @returns ArrayBuffer
 */
export function uint8ToBuf(arr: Uint8Array): ArrayBuffer {
  const buf = new ArrayBuffer(arr.byteLength);
  const view = new Uint8Array(buf);
  view.set(arr);
  return buf;
}

/**
 * Compares two Uint8Arrays for equality.
 * @param a The first Uint8Array.
 * @param b The second Uint8Array.
 * @returns True if the Uint8Arrays are equal, false otherwise.
 */
export function uint8Equals(a: Uint8Array, b: Uint8Array): boolean {
  if (a.length !== b.length) return false;
  for (let i = 0; i < a.length; i++) {
    if (a[i] !== b[i]) return false;
  }
  return true;
}