added profile separate calls method

Author: bahmutov

README.md

@@ -39,6 +39,8 @@ from [addyosmani/timing.js](https://github.com/addyosmani/timing.js).
 * [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.
+* [profile-separate-calls.js](profile-separate-calls.js) can profile actions where separate
+method calls start and stop the operation.
 
 ### Storage measurements
 

bower.json

@@ -1,7 +1,7 @@
 {
   "name": "code-snippets",
   "main": "first-paint.js",
-  "version": "0.3.1",
+  "version": "0.3.2",
   "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": "0.3.1",
+  "version": "0.3.2",
   "author": "Gleb Bahmutov <gleb.bahmutov@gmail.com>",
   "bugs": {
     "url": "https://github.com/bahmutov/code-snippets/issues"

profile-separate-calls.js

@@ -0,0 +1,45 @@
+// time action with separate start and finish callbacks
+// for example
+/*
+  worker.onmessage = function (e) {
+    console.log('worker has finished');
+    renderPrimes(e.data);
+  };
+  document.addEventListener('DOMContentLoaded', function() {
+    document.querySelector('#find').addEventListener('click', function () {
+      var n = Number(document.querySelector('#n').value);
+      primesApp.findFirstPrimes(n);
+    });
+  });
+
+  you can profile as
+
+  timeSeparateCallback(primesApp, 'findFirstPrimes', worker, 'onmessage');
+*/
+(function timeSeparateCallback(obj1, methodName1, obj2, methodName2) {
+  'use strict';
+
+  console.assert(obj1, 'missing first object');
+  console.assert(obj2, 'missing second object');
+
+  var m1 = obj1[methodName1];
+  console.assert(typeof m1 === 'function', 'cannot find first method ' + methodName1);
+  var m2 = obj2[methodName2];
+  console.assert(typeof m2 === 'function', 'cannot find first method ' + methodName2);
+
+  obj1[methodName1] = function () {
+    console.profile('separate');
+    console.time('separate');
+    m1.apply(obj1, arguments);
+  };
+
+  obj2[methodName2] = function () {
+    console.timeEnd('separate');
+    console.profileEnd('separate');
+    m2.apply(obj2, arguments);
+  };
+
+  console.log('wrapped', methodName1, 'and', methodName2, 'in timing calls');
+
+  // modify the arguments below
+}(window, 'postMessage', window, 'onmessage'));