FEATURE: Let users update their emails before confirming

This allows users who entered a typo or invalid email address when
signing up an opportunity to fix it and resending the confirmation
email to that address.

app/assets/javascripts/discourse/controllers/activation-edit.js.es6

@@ -0,0 +1,36 @@
+import computed from 'ember-addons/ember-computed-decorators';
+import ModalFunctionality from 'discourse/mixins/modal-functionality';
+import { ajax } from 'discourse/lib/ajax';
+import { extractError } from 'discourse/lib/ajax-error';
+import { userPath } from 'discourse/lib/url';
+
+export default Ember.Controller.extend(ModalFunctionality, {
+  login: Ember.inject.controller(),
+
+  currentEmail: null,
+  newEmail: null,
+  password: null,
+
+  @computed('newEmail', 'currentEmail')
+  submitDisabled(newEmail, currentEmail) {
+    return newEmail === currentEmail;
+  },
+
+  actions: {
+    changeEmail() {
+      const login = this.get('login');
+
+      ajax(userPath('update-activation-email'), {
+        data: {
+          username: login.get('loginName'),
+          password: login.get('loginPassword'),
+          email: this.get('newEmail')
+        },
+        type: 'PUT'
+      }).then(() => {
+        const modal = this.showModal('activation-resent', {title: 'log_in'});
+        modal.set('currentEmail', this.get('newEmail'));
+      }).catch(err => this.flash(extractError(err), 'error'));
+    }
+  }
+});