angular.isString()
HTML
<script src="https://cdnjs.cloudflare.com/ajax/libs/angular.js/1.4.1/angular.min.js"></script>
<h1>angular.isString()</h1>
JavaScript
console.log(angular.isString('hello')); // true
console.log(angular.isString(new String('hello'))); // false!
console.log(angular.isString(hello));
var foo = new String('foo');
console.log(foo);