use virtual-dom to implement functionality for invite form

src/jade/index.jade

@@ -17,6 +17,9 @@ html
             <br />
             Koodiklinikka on <a target="_blank" href="https://slack.com/">Slack</a>-yhteisö kaikille ohjelmoinnista ja ohjelmistoalasta kiinnostuneille harrastajille ja ammattilaisille.
 
+          #invite-form
+            h3 Liity mukaan
+
       .footer
         a(href='https://koodiklinikka.slack.com') koodiklinikka.slack.com
 

src/js/components/inviteForm.js

@@ -0,0 +1,40 @@
+'use strict';
+
+var {h} = require('virtual-dom');
+var classList = require('../util/classList');
+
+function render(props, state) {
+  var emailInput = h('input', {
+    className: classList({
+      'input': true,
+      'has-success': state.submitted,
+      'has-error': state.error
+    }),
+    type: 'text',
+    name: 'email',
+    placeholder: 'Email',
+    value: state.email,
+    onkeydown: props.onChange
+  });
+
+  var submitButton = h('button', {
+    className: 'btn btn__submit',
+    type: 'submit',
+    title: 'Lähetä',
+    disabled: state.error || state.submitted
+  }, '⏎');
+
+  return h('form', {
+    className: classList({
+      'invite-form': true,
+      'has-success': state.submitted,
+      'has-error': state.error
+    }),
+    onsubmit: props.onSubmit
+  }, [
+    emailInput,
+    submitButton
+  ]);
+}
+
+module.exports = render;

src/js/main.js

@@ -1,19 +1,62 @@
 'use strict';
 
 require('./ga');
+
+var _ = require('lodash');
 var request = require('axios');
-var form = document.getElementById('invite');
 
-form.addEventListener('submit', function(event) {
-  event.preventDefault();
-  form.classList.remove('has-success', 'has-error');
-  var email = event.target.elements.email.value;
+var inviteForm = require('./components/inviteForm');
+var {diff, patch, create} = require('virtual-dom');
+
+var state = {
+  email: '',
+  submitted: false,
+  error: false
+};
+
+function setState(newState) {
+  state = _.extend({}, state, newState);
+  rerender(state);
+}
+
+var props = {
+  onSubmit: function(e) {
+    e.preventDefault();
+
+    setState({
+      submitted: false,
+      error: false
+    });
+
+    request.post('/api/invites', {
+      email: state.email.email
+    }).then(function() {
+      setState({submitted: true});
+    }).catch(function() {
+      setState({error: true});
+    });
+  },
+  onChange: function(e) {
+    setState({
+      email: e.target.value,
+      error: false,
+      submitted: false
+    });
+  },
+};
+
+var tree = inviteForm(props, state);
+var rootNode = create(tree);
+
+document
+  .getElementById('invite-form')
+  .appendChild(rootNode);
+
+function rerender() {
+  var newTree = inviteForm(props, state);
+  var patches = diff(tree, newTree);
+  rootNode = patch(rootNode, patches);
+  tree = newTree;
+}
+
 
-  request.post('/api/invites', {
-    email: email
-  }).then(function() {
-    form.classList.add('has-success');
-  }).catch(function() {
-    form.classList.add('has-error');
-  });
-});

src/js/util/classList.js

@@ -0,0 +1,11 @@
+'use strict';
+
+module.exports = function classList(classesObj) {
+  var classes = [];
+  for(var key in classesObj) {
+    if(!!classesObj[key]) {
+      classes.push(key);
+    }
+  }
+  return classes.join(' ');
+};