added monitor digest cycle

Author: bahmutov

README.md

@@ -26,6 +26,9 @@ Read [Code Snippets tutorial][1],
 [Performance profiling using DevTools code snippets][2] and
 [How to improve Angular application performance using code snippets][3].
 
+Note: code snippets do NOT have access to the full console API, for example no access to 
+`console.monitor`.
+
 ## Snippets
 
 ### DOM and CPU generic performance
@@ -70,6 +73,7 @@ with given name.
 that surrounds given selector. Useful to find parts of the page with expensive watchers.
 * [ng-find-expensive-digest.js](ng-find-expensive-digest.js) builds upon ng-profile-local-digest.js to measure
 digest duration for several selectors and print sorted table starting with the slowest digest duration.
+* [ng-monitor-digest-cycle.js](ng-monitor-digest-cycle.js) - prints a string every time a digest cycle runs.
 * [ng-count-digest-cycles.js](ng-count-digest-cycles.js) - counts number of full digest cycles (from the root scope)
 that run when a scope method executes. Useful because sometimes you can get away with just a local digest
 cycle, rather than a full update. See [Local Angular scopes](http://glebbahmutov.com/blog/local-angular-scopes/).

ng-monitor-digest-cycle.js

@@ -0,0 +1,16 @@
+/*
+  uses console.monitor to print a message every time
+  the digest cycle runs.
+*/
+(function monitorDigestCycle(angular) {
+  var injector = angular.element(document.body).injector();
+  if (!injector) {
+    throw new Error('Missing Angular injector on the document body');
+  }
+  var $rootScope = injector.get('$rootScope');
+  function dummy() {
+    console.log('digest cycle');
+  }
+  window.stopWatching = $rootScope.$watch(dummy);
+  console.log('run window.stopWatching() to stop watching the digest cycle');
+}(window.angular));

package.json

@@ -11,6 +11,7 @@
   "devDependencies": {
     "eslint-rules": "0.3.0",
     "grunt": "0.4.5",
+    "grunt-cli": "0.1.13",
     "grunt-contrib-jshint": "0.11.0",
     "grunt-deps-ok": "0.5.2",
     "grunt-eslint": "2.1.0",