services/utility-service.js

/**
 * AngularJS Service with useful utility functions
 *
 * @module utilityService
 * @see https://docs.angularjs.org/api/ng/type/angular.Module#service
 */
/* eslint-disable no-param-reassign, no-restricted-properties, no-bitwise */
angular.module('tgaApp').service('utilityService', [
  '$window',
  '$document',
  function utilityService($window, $document) {
    /**
     * Check whether browser is likely to be a mobile device (including an iPad).
     *
     * @return {boolean}
     */
    this.isMobile = () => /Mobi|Android/.test($window.navigator.userAgent) || this.isIPad();

    /**
     * Check whether browser is likely to be an iPad.
     *
     * @return {boolean}
     */
    this.isIPad = () => {
      const ua = $window.navigator.userAgent.toLowerCase();
      return (ua.indexOf('ipad') > -1 || ua.indexOf('macintosh') > -1) && 'ontouchend' in $document[0];
    };

    /**
     * Check whether browser claims to be iOS.
     *
     * @return {boolean}
     */
    this.isIOS = () => /iPad|iPhone|iPod/.test($window.navigator.platform) || this.isIPad();

    /**
     * Deep copy an object via JSON serialization and deserialization.
     *
     * @param {*} object - Any JSON-serializable object.
     * @return {*} A deep copy of the object.
     */
    this.deepCopy = (object) => angular.fromJson(angular.toJson(object));

    /**
     * Generate a Version 4 (random) UUID.
     *
     * @return {string} A 36-character UUID string.
     */
    this.generateUUID = () => 'xxxxxxxx-xxxx-4xxx-yxxx-xxxxxxxxxxxx'.replace(/[xy]/g, (c) => {
      const r = (Math.random() * 16) | 0;
      // eslint-disable-next-line no-mixed-operators
      const v = c === 'x' ? r : (r & 0x3) | 0x8;
      return v.toString(16);
    });

    /**
     * SHA256 hashing algorithm.
     *
     * @param {string} ascii - Input string (must only contain 1-byte characters).
     * @return {string} A 64-character hexadecimal string hash result.
     */
    this.sha256 = (ascii) => {
      function rightRotate(value, amount) {
        return (value >>> amount) | (value << (32 - amount));
      }

      const mathPow = Math.pow;
      const maxWord = mathPow(2, 32);
      const lengthProperty = 'length';
      let i;
      let j; // Used as a counter across the whole file
      let result = '';

      const words = [];
      const asciiBitLength = ascii[lengthProperty] * 8;

      //* caching results is optional - remove/add slash from front of this line to toggle
      // Initial hash value: first 32 bits of the fractional parts of the square roots of the first 8 primes
      // (we actually calculate the first 64, but extra values are just ignored)
      let hash = [];
      // Round constants: first 32 bits of the fractional parts of the cube roots of the first 64 primes
      const k = [];
      let primeCounter = k[lengthProperty];
      /*
      var hash = [], k = [];
      var primeCounter = 0;
      */

      const isComposite = {};
      for (let candidate = 2; primeCounter < 64; candidate++) {
        if (!isComposite[candidate]) {
          for (i = 0; i < 313; i += candidate) {
            isComposite[i] = candidate;
          }
          hash[primeCounter] = (mathPow(candidate, 0.5) * maxWord) | 0;
          k[primeCounter++] = (mathPow(candidate, 1 / 3) * maxWord) | 0;
        }
      }

      ascii += '\x80'; // Append Ƈ' bit (plus zero padding)
      while ((ascii[lengthProperty] % 64) - 56) ascii += '\x00'; // More zero padding
      for (i = 0; i < ascii[lengthProperty]; i++) {
        j = ascii.charCodeAt(i);
        if (j >> 8) return null; // ASCII check: only accept characters in range 0-255
        words[i >> 2] |= j << (((3 - i) % 4) * 8);
      }
      words[words[lengthProperty]] = (asciiBitLength / maxWord) | 0;
      words[words[lengthProperty]] = asciiBitLength;

      // process each chunk
      for (j = 0; j < words[lengthProperty];) {
        const w = words.slice(j, (j += 16)); // The message is expanded into 64 words as part of the iteration
        const oldHash = hash;
        // This is now the undefinedworking hash", often labelled as variables a...g
        // (we have to truncate as well, otherwise extra entries at the end accumulate
        hash = hash.slice(0, 8);

        for (i = 0; i < 64; i++) {
          // Expand the message into 64 words
          // Used below if
          const w15 = w[i - 15];
          const w2 = w[i - 2];

          // Iterate
          const a = hash[0];
          const e = hash[4];
          const temp1 = hash[7]
            + (rightRotate(e, 6) ^ rightRotate(e, 11) ^ rightRotate(e, 25)) // S1
            + ((e & hash[5]) ^ (~e & hash[6])) // ch
            + k[i]
            // Expand the message schedule if needed
            + (w[i] = i < 16
              ? w[i]
              : (w[i - 16]
                    + (rightRotate(w15, 7) ^ rightRotate(w15, 18) ^ (w15 >>> 3)) // s0
                    + w[i - 7]
                    + (rightRotate(w2, 17) ^ rightRotate(w2, 19) ^ (w2 >>> 10))) // s1
                  | 0);
          // This is only used once, so *could* be moved below, but it only saves 4 bytes and makes things unreadble
          const temp2 = (rightRotate(a, 2) ^ rightRotate(a, 13) ^ rightRotate(a, 22)) // S0
            + ((a & hash[1]) ^ (a & hash[2]) ^ (hash[1] & hash[2])); // maj
          // We don't bother trimming off the extra ones,
          // they're harmless as long as we're truncating when we do the slice()
          hash = [(temp1 + temp2) | 0].concat(hash);
          hash[4] = (hash[4] + temp1) | 0;
        }

        for (i = 0; i < 8; i++) {
          hash[i] = (hash[i] + oldHash[i]) | 0;
        }
      }

      for (i = 0; i < 8; i++) {
        for (j = 3; j + 1; j--) {
          const b = (hash[i] >> (j * 8)) & 255;
          result += (b < 16 ? 0 : '') + b.toString(16);
        }
      }
      return result;
    };

    /**
     * Durstenfeld shuffle an array.
     * @see https://en.wikipedia.org/wiki/Fisher-Yates_shuffle
     *
     * @param {Array} array - Source array.
     * @return {Array} Shuffled shallow copy of source array.
     */
    this.shuffleArray = (array) => {
      const result = array.concat([]);
      for (let i = result.length - 1; i > 0; i--) {
        const j = Math.floor(Math.random() * (i + 1));
        [result[i], result[j]] = [result[j], result[i]];
      }
      return result;
    };
  },
]);