Adding documentation to root.js

src/js/parser/javascript/root.js

@@ -1,3 +1,6 @@
+// Root nodes contain the top-level [Regexp](./regexp.html) node. Any flags
+// and a few decorative elements are rendered by the root node.
+
 import _ from 'lodash';
 
 export default {
@@ -9,17 +12,22 @@ export default {
     m: 'Multiline'
   },
 
+  // Renders the root into the currently set container.
   _render() {
     var flagText;
 
+    // Render a label for any flags that have been set of the expression.
     if (this.flags.length > 0) {
       flagText = this.container.text(0, 0, `Flags: ${this.flags.join(', ')}`);
     }
 
+    // Render the content of the regular expression.
     return this.regexp.render(this.container.group())
       .then(() => {
         var box;
 
+        // Move rendered regexp to account for flag label and to allow for
+        // decorative elements.
         if (flagText) {
           this.regexp.transform(Snap.matrix()
             .translate(10, flagText.getBBox().height));
@@ -30,6 +38,7 @@ export default {
 
         box = this.regexp.getBBox();
 
+        // Render decorative elements.
         this.container.path(`M${box.ax},${box.ay}H0M${box.ax2},${box.ay}H${box.x2 + 10}`);
         this.container.circle(0, box.ay, 5);
         this.container.circle(box.x2 + 10, box.ay, 5);
@@ -37,6 +46,7 @@ export default {
   },
 
   setup() {
+    // Convert list of flags into text describing each flag.
     this.flags = _(this.properties.flags.textValue).unique().sort().map(flag => {
       return this.flagLabels[flag];
     }).value();