fix: added username config (#2295)

services/users.js

@@ -22,6 +22,10 @@ const {
   ROOT_URL,
   RECAPTCHA_WINDOW,
   RECAPTCHA_INCORRECT_TRIGGER,
+  USERNAME_CAST_REGEXP,
+  USERNAME_REPLACEMENT_CAST_REGEXP,
+  USERNAME_REPLACEMENT_CHARACTER,
+  USERNAME_VALIDATION_REGEX,
 } = require('../config');
 const { jwt: JWT_SECRET } = require('../secrets');
 const debug = require('debug')('talk:services:users');
@@ -525,7 +529,10 @@ class Users {
   }
 
   static castUsername(username) {
-    return username.replace(/ /g, '_').replace(/[^a-zA-Z_]/g, '');
+    return username
+      .trim()
+      .replace(USERNAME_REPLACEMENT_CAST_REGEXP, USERNAME_REPLACEMENT_CHARACTER)
+      .replace(USERNAME_CAST_REGEXP, '');
   }
 
   /**
@@ -554,7 +561,11 @@ class Users {
     for (let i = 0; i < MAX_ATTEMPTS; i++) {
       // Generate `GROUP_ATTEMPTS` guesses for the username.
       const usernameGuesses = Array.from(Array(GROUP_ATTEMPTS)).map(
-        () => `${castedName}_${random(0, END_NUMBER_MAX)}`
+        () =>
+          `${castedName}${USERNAME_REPLACEMENT_CHARACTER}${random(
+            0,
+            END_NUMBER_MAX
+          )}`
       );
 
       // Map them all to lowercase.
@@ -684,13 +695,11 @@ class Users {
    * @return {Promise}
    */
   static async isValidUsername(username, checkAgainstWordlist = true) {
-    const onlyLettersNumbersUnderscore = /^[A-Za-z0-9_]+$/;
-
     if (!username) {
       throw new ErrMissingUsername();
     }
 
-    if (!onlyLettersNumbersUnderscore.test(username)) {
+    if (!USERNAME_VALIDATION_REGEX.test(username)) {
       throw new ErrSpecialChars();
     }