@tetcoin/util/u8a/toHex.js

A collection of useful utilities for @tetcoin

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = u8aToHex;
// Copyright 2017-2019 @polkadot/util authors & contributors
// This software may be modified and distributed under the terms
// of the Apache-2.0 license. See the LICENSE file for details.
const ALPHABET = '0123456789abcdef';
/**
 * @name u8aToHex
 * @summary Creates a hex string from a Uint8Array object.
 * @description
 * `UInt8Array` input values return the actual hex string. `null` or `undefined` values returns an `0x` string.
 * @example
 * <BR>
 *
 * ```javascript
 * import { u8aToHex } from '@tetcoin/util';
 *
 * u8aToHex(new Uint8Array([0x68, 0x65, 0x6c, 0x6c, 0xf])); // 0x68656c0f
 * ```
 */

function u8aToHex(value) {
  let bitLength = arguments.length > 1 && arguments[1] !== undefined ? arguments[1] : -1;
  let isPrefixed = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : true;
  const prefix = isPrefixed ? '0x' : '';

  if (!value || !value.length) {
    return prefix;
  }

  const byteLength = Math.ceil(bitLength / 8);

  if (byteLength > 0 && value.length > byteLength) {
    const halfLength = Math.ceil(byteLength / 2);
    return "".concat(u8aToHex(value.subarray(0, halfLength), -1, isPrefixed), "\u2026").concat(u8aToHex(value.subarray(value.length - halfLength), -1, false));
  } // based on comments in https://stackoverflow.com/questions/40031688/javascript-arraybuffer-to-hex and
  // implementation in http://jsben.ch/Vjx2V - optimisation here suggests that a forEach loop is faster
  // than reduce as well (clocking at in 90% of the reduce speed with tweaking in the playpen above)


  return value.reduce((result, value) => {
    return result + ALPHABET[value >> 4] + ALPHABET[value & 15];
  }, prefix);
}