Header plugin (#348)

* isFunction function

* use header from cdn

build/codex-editor.js

@@ -11259,8 +11259,8 @@ var CodexEditor = function () {
       for (var toolName in this.config.tools) {
         var tool = this.config.tools[toolName];
 
-        if (!_.isClass(tool) && !_.isClass(tool.class)) {
-          return Promise.reject('Tool \xAB' + toolName + '\xBB must be a class or an object with a \xABclass\xBB property');
+        if (!_.isFunction(tool) && !_.isFunction(tool.class)) {
+          return Promise.reject('Tool \xAB' + toolName + '\xBB must be a constructor function or an object with that function in the \xABclass\xBB property');
         }
       }
 
@@ -20451,6 +20451,18 @@ var Util = function () {
       return Array.prototype.slice.call(collection);
     }
 
+    /**
+     * Check if passed variable is a function
+     * @param {*} fn
+     * @return {boolean}
+     */
+
+  }, {
+    key: 'isFunction',
+    value: function isFunction(fn) {
+      return typeof fn === 'function';
+    }
+
     /**
      * Check if passed function is a class
      * @param {function} fn

example/example.html

@@ -38,6 +38,8 @@
   <script src="plugins/header/header.js?v=100"></script>
   <link rel="stylesheet" href="plugins/header/header.css">
 
+  <script src="https://cdn.rawgit.com/codex-editor/header/25d39a1e/dist/bundle.js"></script>
+
   <script src="plugins/simple-image/simple-image.js?v=100"></script>
   <link rel="stylesheet" href="plugins/simple-image/simple-image.css">