Adding progress indicator

src/js/parser/javascript/base.js

@@ -1,6 +1,9 @@
 import _ from 'lodash';
 import Q from 'q';
 
+var renderCounter = 0,
+    maxCounter = 0;
+
 export default {
   setContainer(container) {
     this.container = container;
@@ -85,17 +88,40 @@ export default {
     console.log(box, anchorLine.node);
   },
 
+  startRender() {
+    renderCounter++;
+  },
+
+  doneRender() {
+    if (maxCounter === 0) {
+      maxCounter = renderCounter;
+    }
+
+    renderCounter--;
+    document.body.dispatchEvent(new CustomEvent('updateStatus', {
+      detail: {
+        percentage: (maxCounter - renderCounter) / maxCounter
+      }
+    }));
+
+    if (renderCounter === 0) {
+      maxCounter = 0;
+    }
+  },
+
   render(container) {
     if (container) {
       this.setContainer(container);
     }
 
+    this.startRender();
     return this._render()
       .then((() => {
         if (this.anchorDebug) {
           this.renderAnchor();
         }
       }).bind(this))
+      .then(this.doneRender.bind(this))
       .then(_.constant(this));
   },
 

src/js/regexper.js

@@ -10,6 +10,7 @@ export default class Regexper {
     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.percentage = root.querySelector('#progress div');
     this.svg = root.querySelector('#regexp-render svg');
 
     this.padding = 10;
@@ -46,12 +47,18 @@ export default class Regexper {
     }
   }
 
+  updatePercentage(event) {
+    this.percentage.style.width = event.detail.percentage * 100 + '%';
+  }
+
   bindListeners() {
     this.field.addEventListener('keypress', this.keypressListener.bind(this));
 
     this.form.addEventListener('submit', this.submitListener.bind(this));
 
     window.addEventListener('hashchange', this.hashchangeListener.bind(this));
+
+    this.root.addEventListener('updateStatus', this.updatePercentage.bind(this));
   }
 
   setState(state) {