Possibly unhandled rejection -- Error when creating a form with angularjs
<p>I created this simple web application to put data into a firebase database. The problem is that I get a error when I open the webpage in my browser. This is the error I get</p>

<pre><code>Possibly unhandled rejection: {} angular.js:14324
</code></pre>

<p>Also when I press the sumbit button the first time with no data in the fields it displays the same error as shown above. Then when I press the button again it does submit the empty fields to the database. I think angular finds it a problem that the fields are empty. Am I missing something? Putting text in the fields works fine and it also submits to the database. It's just with empty fields that their are problems.</p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-js lang-js prettyprint-override"><code>var app = angular.module("sampleApp", ["firebase"]);
app.controller("SampleCtrl", function($scope, $firebaseArray) {
    var ref = firebase.database().ref().child("messages");
    $scope.loading = true;
    $firebaseArray(ref).$loaded().then(function(){
        $scope.loading = false;
        document.getElementById('loader').style.display = 'none';
    });
    $scope.messages = $firebaseArray(ref);
    $scope.addMessage = function() {
        $scope.messages.$add({
            name: $scope.name,
            company: $scope.company,
            reason: $scope.reason,
            wayofcontact: $scope.wayofcontact,
        });
        $scope.name = '';
        $scope.company = '';
        $scope.reason = '';
        $scope.wayofcontact = '';
        document.getElementById("name").focus();
    };
});</code></pre>
<pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;!DOCTYPE html&gt;
&lt;html ng-app="sampleApp"&gt;
&lt;head&gt;
    &lt;meta charset="utf-8"&gt;
    &lt;title&gt;AngularJS Tutorial&lt;/title&gt;
    &lt;script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.0/angular.min.js"&gt;&lt;/script&gt;
    &lt;link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-alpha.5/css/bootstrap.min.css" integrity="sha384-AysaV+vQoT3kOAXZkl02PThvDr8HYKPZhNT5h/CXfBThSRXQ6jW5DO2ekP5ViFdi" crossorigin="anonymous"&gt;
    &lt;meta name="viewport" content="width=device-width, initial-scale=1.0"/&gt;
    &lt;style&gt;
    [ng\:cloak], [ng-cloak], [data-ng-cloak], [x-ng-cloak], .ng-cloak, .x-ng-cloak {
        display: none !important;
    }
    ul {
        list-style-type: none;
    }
    &lt;/style&gt;
&lt;/head&gt;
&lt;body ng-controller="SampleCtrl" ng-cloak &gt;
    &lt;div class="container" ng-view&gt;
        &lt;div ng-show="loading"&gt;
            Loading...
        &lt;/div&gt;
        &lt;ul class="list-unstyled"&gt;
            &lt;li ng-repeat="message in messages | filter:{name: '!!'}"&gt;
                &lt;h1&gt;{{message.name}}&lt;/h1&gt;
                &lt;p&gt;
                    Bedrijf: {{message.company}}&lt;br&gt;
                    Reden: {{message.reason}}&lt;br&gt;
                    Email/telefoon: {{message.wayofcontact}}&lt;br&gt;
                &lt;/p&gt;
                &lt;button ng-click="messages.$remove(message)" class="btn btn-danger"&gt;Verwijder verzoek&lt;/button&gt;
                &lt;br&gt;&lt;br&gt;
            &lt;/li&gt;
        &lt;/ul&gt;
        &lt;form ng-submit="addMessage()" novalidate&gt;
            &lt;div class="row"&gt;
                &lt;div class="col-xs-6 form-group"&gt;
                    &lt;input type="text" class="form-control" id="name" ng-model="name" placeholder="Naam" autofocus required/&gt;
                &lt;/div&gt;
                &lt;div class="col-xs-6"&gt;
                    &lt;input type="text" class="form-control" ng-model="namecolleague" placeholder="Naam collega" required/&gt;
                &lt;/div&gt;
                &lt;div class="col-xs-12 form-group"&gt;
                    &lt;input type="text" class="form-control" ng-model="company" placeholder="Bedrijf" required/&gt;
                &lt;/div&gt;
                &lt;div class="col-xs-12 form-group"&gt;
                    &lt;textarea rows="3" type="text" class="form-control" ng-model="reason" placeholder="Reden van bellen" required&gt;&lt;/textarea&gt;
                &lt;/div&gt;
                &lt;div class="col-xs-12 form-group"&gt;
                    &lt;input type="text" class="form-control" ng-model="wayofcontact" placeholder="Email of nummer" required/&gt;
                &lt;/div&gt;
                &lt;div class="col-xs-12 form-group"&gt;
                    &lt;button type="submit" class="btn btn-primary"&gt;Add Message&lt;/button&gt;
                &lt;/div&gt;
            &lt;/div&gt;
        &lt;/form&gt;
    &lt;/div&gt;
    &lt;script type="text/javascript" src="https://www.gstatic.com/firebasejs/3.6.0/firebase.js"&gt;&lt;/script&gt;
    &lt;script type="text/javascript" src="https://cdn.firebase.com/libs/angularfire/2.1.0/angularfire.min.js"&gt;&lt;/script&gt;
    &lt;script type="text/javascript" src="scripts/app.js"&gt;&lt;/script&gt;
    &lt;script&gt;
    // Initialize Firebase
    var config = {
        apiKey: "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx",
        authDomain: "xxxxxxxxxxxxxxxxxxxx",
        databaseURL: "xxxxxxxxxxxxxxxxxxxxxxxxxxx",
        storageBucket: "xxxxxxxxxxxxxxxx",
        messagingSenderId: "xxxxxxxxxxx"
    };
    firebase.initializeApp(config);
    &lt;/script&gt;
&lt;/body&gt;
&lt;/html&gt;</code></pre>
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