added prototype method profiling snippet

Author: bahmutov

README.md

@@ -37,6 +37,8 @@ Read [Code Snippets tutorial][1],
 from [addyosmani/timing.js](https://github.com/addyosmani/timing.js).
 * [time-method-call.js](time-method-call.js) - measures single method call time.
 * [profile-method-call.js](profile-method-call.js) - profiles a single method call.
+* [profile-prototype-method.js](profile-prototype-method.js) - profiles a single method call 
+that is on a prototype object, not on an instance.
 
 ### Storage measurements
 

bower.json

@@ -1,7 +1,7 @@
 {
   "name": "code-snippets",
   "main": "first-paint.js",
-  "version": "0.3.0",
+  "version": "0.3.1",
   "homepage": "https://github.com/bahmutov/code-snippets",
   "license": "MIT",
   "ignore": [

package.json

@@ -1,7 +1,7 @@
 {
   "name": "code-snippets",
   "description": "Chrome DevTools code snippets ",
-  "version": "0.3.0",
+  "version": "0.3.1",
   "author": "Gleb Bahmutov <gleb.bahmutov@gmail.com>",
   "bugs": {
     "url": "https://github.com/bahmutov/code-snippets/issues"

profile-prototype-method.js

@@ -0,0 +1,34 @@
+/*
+  Almost the same as profile method call, but for wrapping methods that are on prototype
+  function Foo() {}
+  Foo.prototype.getName = function () { return this.name; }
+  var foo = new Foo();
+  foo.getName();
+
+  // profile getName without getting foo reference
+  profilePrototypeCall with proto = Foo.prototype;
+  and method name 'getName'
+*/
+(function profilePrototypeCall(proto, methodName) {
+  'use strict';
+
+  console.assert(proto, 'cannot find prototype to profile');
+  console.assert(typeof methodName === 'string', 'expected method name');
+
+  var originalMethod = proto[methodName];
+  console.assert(typeof originalMethod === 'function', 'cannot find method ' + methodName);
+
+  proto[methodName] = function () {
+    console.profile(methodName);
+
+    originalMethod.apply(this, arguments);
+
+    console.profileEnd(methodName);
+
+    proto[methodName] = originalMethod;
+    console.log('restored the prototype method call', methodName);
+  };
+  console.log('wrapped', methodName + ' in profiling calls');
+
+  // some prototype and method name
+}(this.Photostack.prototype, '_rotateItem'));