Add API Call to retrieve auto-complete options for usernames

website/server/controllers/api-v4/members.js

@@ -0,0 +1,34 @@
+import {model as User} from '../../models/user';
+
+let api = {};
+
+
+api.getUsernameAutocompletes = {
+  method: 'GET',
+  url: '/members/find/:username',
+  middlewares: [],
+  async handler (req, res) {
+    req.checkParams('username', res.t('invalidReqParams')).notEmpty();
+
+    let validationErrors = req.validationErrors();
+    if (validationErrors) throw validationErrors;
+
+    let username = req.params.username.toLowerCase();
+    if (username[0] === '@') username = username.slice(1, username.length);
+
+    if (username.length < 2) {
+      res.respond(200, []);
+      return;
+    }
+
+    let members = await User
+      .find({'auth.local.lowerCaseUsername': {$regex: `.*${username}.*`}, 'flags.verifiedUsername': true})
+      .select(['profile.name', 'contributor', 'auth.local.username'])
+      .limit(20)
+      .exec();
+
+    res.respond(200, members);
+  },
+};
+
+module.exports = api;