extract glyphicons.yml generator out of Gruntfile into separate module

docs/grunt/bs-glyphicons-data-generator.js

@@ -0,0 +1,27 @@
+/* jshint node: true */
+
+var fs = require('fs')
+
+module.exports = function generateGlyphiconsData() {
+  // Pass encoding, utf8, so `readFileSync` will return a string instead of a
+  // buffer
+  var glyphiconsFile = fs.readFileSync('less/glyphicons.less', 'utf8')
+  var glpyhiconsLines = glyphiconsFile.split('\n')
+
+  // Use any line that starts with ".glyphicon-" and capture the class name
+  var iconClassName = /^\.(glyphicon-[^\s]+)/
+  var glyphiconsData = '# This file is generated via Grunt task. **Do not edit directly.** \n' +
+                       '# See the \'build-glyphicons-data\' task in Gruntfile.js.\n\n';
+  for (var i = 0, len = glpyhiconsLines.length; i < len; i++) {
+    var match = glpyhiconsLines[i].match(iconClassName)
+
+    if (match != null) {
+      glyphiconsData += '- ' + match[1] + '\n'
+    }
+  }
+
+  // Create the `_data` directory if it doesn't already exist
+  if (!fs.existsSync('docs/_data')) fs.mkdirSync('docs/_data')
+
+  fs.writeFileSync('docs/_data/glyphicons.yml', glyphiconsData)
+}