Ghost/ghost/admin/app/routes/signup.js

import DS from 'ember-data';
import EmberObject from '@ember/object';
import RSVP from 'rsvp';
import Route from '@ember/routing/route';
import UnauthenticatedRouteMixin from 'ghost-admin/mixins/unauthenticated-route-mixin';
import ValidationEngine from 'ghost-admin/mixins/validation-engine';
import {inject as service} from '@ember/service';

const {Promise} = RSVP;
const {Errors} = DS;

export default Route.extend(UnauthenticatedRouteMixin, {
    ghostPaths: service(),
    notifications: service(),
    session: service(),
    ajax: service(),
    config: service(),

    beforeModel() {
        if (this.get('session.isAuthenticated')) {
            this.notifications.showAlert('You need to sign out to register as a new user.', {type: 'warn', delayed: true, key: 'signup.create.already-authenticated'});
        }

        this._super(...arguments);
    },

    model(params) {
        let SignupDetails = EmberObject.extend(ValidationEngine, {
            validationType: 'signup'
        });
        let signupDetails = SignupDetails.create();
        let re = /^(?:[A-Za-z0-9_-]{4})*(?:[A-Za-z0-9_-]{2}|[A-Za-z0-9_-]{3})?$/;
        let email,
            tokenText;

        return new Promise((resolve) => {
            if (!re.test(params.token)) {
                this.notifications.showAlert('Invalid token.', {type: 'error', delayed: true, key: 'signup.create.invalid-token'});

                return resolve(this.transitionTo('signin'));
            }

            tokenText = atob(params.token);
            email = tokenText.split('|')[1];

            // leave e-mail blank even though we get it from the token because
            // we need the user to type it in for Chrome to remember the
            // email/password combo properly
            signupDetails.set('email', '');
            signupDetails.set('token', params.token);
            signupDetails.set('errors', Errors.create());

            let authUrl = this.get('ghostPaths.url').api('authentication', 'invitation');

            return this.ajax.request(authUrl, {
                dataType: 'json',
                data: {
                    email
                }
            }).then((response) => {
                if (response && response.invitation && response.invitation[0].valid === false) {
                    this.notifications.showAlert('The invitation does not exist or is no longer valid.', {type: 'warn', delayed: true, key: 'signup.create.invalid-invitation'});

                    return resolve(this.transitionTo('signin'));
                }

                // set blogTitle, so password validation has access to it
                signupDetails.set('blogTitle', this.get('config.blogTitle'));

                resolve(signupDetails);
            }).catch(() => {
                resolve(signupDetails);
            });
        });
    },

    deactivate() {
        this._super(...arguments);

        // clear the properties that hold the sensitive data from the controller
        this.controllerFor('signup').get('signupDetails').setProperties({email: '', password: '', token: ''});
    },

    buildRouteInfoMetadata() {
        return {
            bodyClasses: ['unauthenticated-route']
        };
    }
});