Adding initial UI JS

This still needs lots of tests to be written, and checks for missing
browser functionality (specifically around Blob URLs)

package.json

@@ -28,6 +28,7 @@
     "karma-notify-reporter": "^0.1.1",
     "karma-phantomjs-launcher": "^0.1.4",
     "lodash": "^2.4.1",
+    "q": "^1.1.2",
     "snapsvg": "git://github.com/adobe-webplatform/Snap.svg#dev",
     "through": "^2.3.6",
     "vinyl-transform": "^1.0.0"

src/index.html

@@ -1,10 +1,10 @@
 <div class="container">
-  <form id="regexp_form">
+  <form id="regexp-form">
     <textarea id="regexp-input" autofocus="autofocus" placeholder="Enter JavaScript-style regular expression to display"></textarea>
     <button type="submit">Display</button>
 
     <ul class="inline-list">
-      <li><a href="#" class="oi with-text" data-glyph="data-transfer-download">Download</a></li>
+      <li><a href="#" class="oi with-text" data-glyph="data-transfer-download" download="image.svg" type="image/svg+xml">Download</a></li>
       <li><a href="#" class="oi with-text" data-glyph="link-intact">Permalink</a></li>
     </ul>
   </form>

src/js/main.js

@@ -1,28 +1,10 @@
-import parser from './parser/javascript.js';
-import Snap from 'snapsvg';
+import Regexper from './regexper.js';
 
-// Testing code
 (function() {
-  var result = parser.parse('^test?(foo)[a-z]asdf$'),
-      svg = Snap('#regexp-render svg');
+  var regexper = new Regexper(document.body);
+  regexper.bindListeners();
 
-  if (svg) {
-    document.body.className = 'has-results';
-
-    result.container = svg.group().transform(Snap.matrix()
-      .translate(10, 10));
-    result.render();
-
-    setTimeout(() => {
-      var box;
-
-      result.position();
-
-      box = result.container.getBBox();
-      svg.attr({
-        width: box.width + 20,
-        height: box.height + 20
-      });
-    });
-  }
+  setTimeout(() => {
+    window.dispatchEvent(new Event('hashchange'));
+  });
 }());

src/js/regexper.js

@@ -0,0 +1,117 @@
+import parser from './parser/javascript.js';
+import Snap from 'snapsvg';
+import Q from 'q';
+
+export default class Regexper {
+  constructor(root) {
+    this.root = root;
+    this.form = root.querySelector('#regexp-form');
+    this.field = root.querySelector('#regexp-input');
+    this.error = root.querySelector('#error');
+    this.permalink = root.querySelector('a[data-glyph="link-intact"]');
+    this.download = root.querySelector('a[data-glyph="data-transfer-download"]');
+    this.svg = root.querySelector('#regexp-render svg');
+
+    this.padding = 10;
+    this.snap = Snap(this.svg);
+  }
+
+  keypressListener(event) {
+    if (event.shiftKey && event.keyCode === 13) {
+      event.preventDefault();
+      this.form.dispatchEvent(new Event('submit'));
+    }
+  }
+
+  submitListener(event) {
+    event.preventDefault();
+
+    location.hash = this.field.value;
+  }
+
+  hashchangeListener() {
+    var expression = decodeURIComponent(location.hash.slice(1)).replace(/[\r\n]/g, '');
+
+    if (expression !== '') {
+      this.field.value = expression;
+
+      this.setState('is-loading');
+
+      this.renderRegexp(expression)
+        .then((() => {
+          this.setState('has-results');
+          this.updateLinks();
+        }).bind(this), this.showError.bind(this));
+    }
+  }
+
+  bindListeners() {
+    this.field.addEventListener('keypress', this.keypressListener.bind(this));
+
+    this.form.addEventListener('submit', this.submitListener.bind(this));
+
+    window.addEventListener('hashchange', this.hashchangeListener.bind(this));
+  }
+
+  setState(state) {
+    var classList = this.root.classList;
+
+    classList.remove('is-loading', 'has-results', 'has-error');
+    classList.add(state);
+  }
+
+  showError(message) {
+    this.setState('has-error');
+    this.error.innerHTML = '';
+    this.error.appendChild(document.createTextNode(message));
+  }
+
+  updateLinks() {
+    var blob, url;
+
+    blob = new Blob([svg.outerHTML], { type: 'image/svg+xml' });
+    url = URL.createObjectURL(blob);
+
+    this.download.setAttribute('href', url);
+    this.permalink.setAttribute('href', location);
+  }
+
+  renderSvg(snap, expression) {
+    var result;
+
+    snap.selectAll('g').remove();
+
+    result = parser.parse(expression);
+    result.container = snap.group().transform(Snap.matrix()
+      .translate(this.padding, this.padding));
+    result.render();
+
+    return result;
+  }
+
+  positionSvg(snap, parsed) {
+    var box;
+
+    parsed.position();
+
+    box = parsed.container.getBBox();
+    snap.attr({
+      width: box.width + this.padding * 2,
+      height: box.height + this.padding * 2
+    });
+  }
+
+  renderRegexp(expression) {
+    var padding = this.padding,
+        snap = Snap(this.svg),
+        promise;
+
+    promise = Q.promise(((resolve, reject, notify) => {
+      resolve(this.renderSvg(snap, expression));
+    }).bind(this));
+
+    promise.then(this.positionSvg.bind(this, snap));
+
+    return promise;
+  }
+}

src/sass/main.scss

@@ -175,7 +175,9 @@ header {
 #error {
   background: $red;
   color: $white;
-  text-indent: 0.5em;
+  padding: 0 0.5em;
+  white-space: pre;
+  font-family: monospace;
   font-weight: bold;
   display: none;
 
@@ -192,7 +194,7 @@ header {
 
   body.is-loading &, body.has-error & {
     position: absolute;
-    top: -100px;
+    top: -10000px;
   }
 }