Moving sharedID generation within sharedId module

modules/sharedIdSystem.js

@@ -8,13 +8,12 @@
 import * as utils from '../src/utils.js'
 import {ajax} from '../src/ajax.js';
 import {submodule} from '../src/hook.js';
-import * as sharedIdGenerator from '../src/sharedIdGenerator.js';
 
 const MODULE_NAME = 'sharedId';
 const ID_SVC = 'https://id.sharedid.org/id';
 const DEFAULT_24_HOURS = 86400;
 const OPT_OUT_VALUE = '00000000000000000000000000';
-
+const id = factory();
 /**
  * Constructs cookie value
  * @param value
@@ -91,7 +90,7 @@ function idGenerationCallback(callback) {
       callback(value);
     },
     error: function (statusText, responseBody) {
-      const value = constructCookieValue(sharedIdGenerator.id(), true);
+      const value = constructCookieValue(id(), true);
       utils.logInfo('SharedId: Ulid Generated SharedId: ' + value.id);
       callback(value);
     }
@@ -152,6 +151,131 @@ function encodeId(value) {
   return sharedId;
 }
 
+// These values should NEVER change. If
+// they do, we're no longer making ulids!
+const ENCODING = '0123456789ABCDEFGHJKMNPQRSTVWXYZ'; // Crockford's Base32
+const ENCODING_LEN = ENCODING.length;
+const TIME_MAX = Math.pow(2, 48) - 1;
+const TIME_LEN = 10;
+const RANDOM_LEN = 16;
+
+/**
+ * the factory to generate unique identifier based on time and current pseudorandom number
+ * @param {string} the current pseudorandom number generator
+ * @returns {function(*=): *}
+ */
+function factory(currPrng) {
+  if (!currPrng) {
+    currPrng = detectPrng();
+  }
+  return function ulid(seedTime) {
+    if (isNaN(seedTime)) {
+      seedTime = Date.now();
+    }
+    return encodeTime(seedTime, TIME_LEN) + encodeRandom(RANDOM_LEN, currPrng);
+  };
+}
+
+/**
+ * creates and logs the error message
+ * @function
+ * @param {string} error message
+ * @returns {Error}
+ */
+function createError(message) {
+  utils.logError(message);
+  const err = new Error(message);
+  err.source = 'sharedId';
+  return err;
+}
+
+/**
+ * gets a a random charcter from generated pseudorandom number
+ * @param {string} the generated pseudorandom number
+ * @returns {string}
+ */
+function randomChar(prng) {
+  let rand = Math.floor(prng() * ENCODING_LEN);
+  if (rand === ENCODING_LEN) {
+    rand = ENCODING_LEN - 1;
+  }
+  return ENCODING.charAt(rand);
+}
+
+/**
+ * encodes the time based on the length
+ * @param now
+ * @param len
+ * @returns {string} encoded time.
+ */
+function encodeTime (now, len) {
+  if (isNaN(now)) {
+    throw new Error(now + ' must be a number');
+  }
+
+  if (Number.isInteger(now) === false) {
+    throw createError('time must be an integer');
+  }
+
+  if (now > TIME_MAX) {
+    throw createError('cannot encode time greater than ' + TIME_MAX);
+  }
+  if (now < 0) {
+    throw createError('time must be positive');
+  }
+
+  if (Number.isInteger(len) === false) {
+    throw createError('length must be an integer');
+  }
+  if (len < 0) {
+    throw createError('length must be positive');
+  }
+
+  let mod;
+  let str = '';
+  for (; len > 0; len--) {
+    mod = now % ENCODING_LEN;
+    str = ENCODING.charAt(mod) + str;
+    now = (now - mod) / ENCODING_LEN;
+  }
+  return str;
+}
+
+/**
+ * encodes random character
+ * @param len
+ * @param prng
+ * @returns {string}
+ */
+function encodeRandom (len, prng) {
+  let str = '';
+  for (; len > 0; len--) {
+    str = randomChar(prng) + str;
+  }
+  return str;
+}
+
+/**
+ * detects the pseudorandom number generator and generates the random number
+ * @function
+ * @param {string} error message
+ * @returns {string} a random number
+ */
+function detectPrng(root) {
+  if (!root) {
+    root = typeof window !== 'undefined' ? window : null;
+  }
+  const browserCrypto = root && (root.crypto || root.msCrypto);
+  if (browserCrypto) {
+    return () => {
+      const buffer = new Uint8Array(1);
+      browserCrypto.getRandomValues(buffer);
+      return buffer[0] / 0xff;
+    };
+  }
+  return () => Math.random();
+}
+
 /** @type {Submodule} */
 export const sharedIdSubmodule = {
   /**