Can't watch a promise

scope.$watch doesn't like promises

by jdmarshall

HTML

<script src="https://code.angularjs.org/1.2.12/angular.js"></script>
<div ng-controller="MyCtrl">
    <h2>Can't watch a promise</h2>
    <div class="output">Output: {{output}}</div>
    <div class="input">
        <button ng-click='doClick()'>Click me</button>
    </div>
</div>

CSS

body{
    padding: 10px;
}

.input, .output {
    padding: 10px;
}

.output {
    height: 20px;
}

JavaScript

var myApp = angular.module('myApp',[]);

function MyCtrl($scope, $q) {
    var deferred = $q.defer();

    $scope.$watch(deferred.promise, function(value) {
        $scope.value = value;
    });
    
    $scope.doClick = function() {
        deferred.resolve("resolved");
    };
}