[Fix] node < 4 lacks Array.prototype.find

Author: ljharb

lib/util/variable.js

@@ -4,6 +4,8 @@
  */
 'use strict';
 
+var find = require('array.prototype.find');
+
 /**
  * Search a particular variable in a list
  * @param {Array} variables The variables list.
@@ -23,7 +25,7 @@ function findVariable(variables, name) {
  * @returns {Object} Variable if the variable was found, null if not.
  */
 function getVariable(variables, name) {
-  return variables.find(function (variable) {
+  return find(variables, function (variable) {
     return variable.name === name;
   });
 }