discourse/app/assets/javascripts/discourse/components/create-account.js.es6

export default Ember.Component.extend({
  classNames: ['create-account'],

  didInsertElement() {
    this._super();

    if ($.cookie('email')) {
      this.set('email', $.cookie('email'));
    }

    this.$().on('keydown.discourse-create-account', e => {
      if (!this.get('disabled') && e.keyCode === 13) {
        e.preventDefault();
        e.stopPropagation();
        this.sendAction();
        return false;
      }
    });
  },

  willDestroyElement() {
    this._super();
    this.$().off('keydown.discourse-create-account');
  }
});