$log Service:

AngularJs includes logging service $log, which logs the messages to the browser's console.

The $log service includes different methods to log the error, information, warning or debug information. It can be useful in debugging and auditing.

Example: $log

<!DOCTYPE html>
<html>
<head>
    <script src="~/Scripts/angular.js"></script>
</head>
<body ng-app="myApp" >
    <div ng-controller="myController">
        <p>Please check the browser console for the logging information.</p>
    </div>
    <script>
        var myApp = angular.module('myApp', []);

        myApp.controller("myController", function ($log) {
            
            $log.log('This is log.');
            $log.error('This is error.');
            $log.info('This is info.');
            $log.warn('This is warning.');
            $log.debug('This is debugging.');

        });
    </script>
</body>
</html>

 
Try it 

In the above example, controller function includes $log parameter which will be supplied by AngularJS framework.