Cannot set property of null in angular-2 when using this?
Question
Hi I'm getting an error in
angular2-polyfills.js:143 Uncaught TypeError: Cannot set property 'singlehotel' of null(…)
and a warning from Firebase
FIREBASE WARNING: Exception was thrown by user callback. TypeError: Cannot set property 'singlehotel' of null
When I tried to get the data from Firebase I am getting this error, any one please help to to resolve this.
Thanks in advance!
here is my code
ngAfterContentInit() {
this.singlehotel = {};
firebase.database().ref('Rests/').once('value', function(snapshot) {
console.log('value from db' + JSON.stringify(snapshot.val()));
var getrest = snapshot.val();
console.log(JSON.stringify(getrest));
for (var key in getrest) {
if(restemail == getrest[key].email){
console.log(key + ':' + JSON.stringify(getrest[key]));
this.singlehotel = getrest[key]; //getting error here when using this
}
}
});
};
index.html
<script src="https://www.gstatic.com/firebasejs/3.5.1/firebase.js"></script>
<script>
// Initialize Firebase
// for security reasons i am hiding my keys
var config = {
apiKey: "***",
authDomain: "***",
databaseURL: "***",
storageBucket: "**",
messagingSenderId: "**"
};
firebase.initializeApp(config);
</script>
<body>
<my-app>Loading...</my-app>
</body>
view
<div class="container" style="background-color: #f2f2f2;">
<h1><b>Hotel Name :{{singlehotel.displayName}}</b></h1>
</div>
both belongs to same componet.when the view gets loaded the ngAfterContentInit() function willi be called every time , thats how the function triggers but i am not able to store in scope i mean this.please help me
1 answers
solution1
4 ACCPTED 2016-11-02 10:00:20
this doesn't point to the current class instance if you use function() {... } . Use arrow functions instead
firebase.database().ref('Rests/').once('value', (snapshot) => {
See also https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Functions/Arrow_functions
The technical post webpages of this site follow the CC BY-SA 4.0 protocol. If you need to reprint, please indicate the site URL or the original address.Any question please contact:yoyou2525@163.com.