accounts_hooks.js

import { Meteor } from 'meteor/meteor';
import { Accounts } from 'meteor/accounts-base';

Accounts.onCreateUser((options, user) => {
  // Create empty user profile if none exists
  user.profile = user.profile || {};

  // Check services object exists
  if (user.services) {
    // Case 1: Register with Github
    if (user.services.github) {
      // Set user email address from Github email
      user.emails = [
        {
          address: user.services.github.email,
          verified: true,
        },
      ];
      // Search 'githubUsername' from database.
      const githubUsername = user.services.github.username;
      const existingUser = Meteor.users.findOne({ username: githubUsername });
      if (existingUser === undefined) {
        // Username available, set username to Github username.
        user.username = githubUsername;
      } else {
        // Username clashes with existing username, add prefix
        user.username = `gh-${githubUsername}`;
      }
    // Case 2: Register with local account, email verification required
    } else if (user.services.password) {
      // we wait for Meteor to create the user before sending an email
      Meteor.setTimeout(() => {
        Meteor.call('sendRegistrationEmailVerification', user._id);
      }, 2 * 1000);
    }
  }

  return user;
});