util.js

'use strict'

const textDecoder = new TextDecoder()
/**
 * @param {ArrayBufferView|ArrayBuffer} bytes
 * @returns {string}
 */
const decodeText = (bytes) => textDecoder.decode(bytes)

const textEncoder = new TextEncoder()
/**
 * @param {string} text
 * @returns {Uint8Array}
 */
const encodeText = (text) => textEncoder.encode(text)

/**
 * Returns a new Uint8Array created by concatenating the passed Arrays
 *
 * @param {Array<ArrayLike<number>>} arrs
 * @param {number} length
 * @returns {Uint8Array}
 */
function concat (arrs, length) {
  const output = new Uint8Array(length)
  let offset = 0

  for (const arr of arrs) {
    output.set(arr, offset)
    offset += arr.length
  }

  return output
}

module.exports = { decodeText, encodeText, concat }