this becomes null inside the javascript function

Question

I have java script function which gives current lat long inside that function making an http post call like this \"this.http.post\" but the value of this null inside the

Answer 1

Simply store this into a variable and use it inside the callback function. Its' quite handy

ngOnInit():void {
var self = this;
if (navigator.geolocation) {
      navigator.geolocation.getCurrentPosition(function (p) {
          var LatLng = new google.maps.LatLng(p.coords.latitude, p.coords.longitude);

          console.log(p.coords.latitude);
          console.log(p.coords.longitude);

            var dataObj = {
                latitude :p.coords.latitude,
                longitude:p.coords.longitude
                        };
          self.http.post('https://XXXXX/datacenteres.php', {
    dataObj
    })
      .subscribe(
        res => {
          console.log(res);
        },
        err => {
          console.log("Error occured");
        }
      );

  }
  }

}

Answer 2

You can use arrow function like below:

if (navigator.geolocation) {
      navigator.geolocation.getCurrentPosition(p => {
        //var LatLng = new google.maps.LatLng(p.coords.latitude, p.coords.longitude);
        console.log(p.coords.latitude);
        console.log(p.coords.longitude);
        var dataObj = {
          latitude :p.coords.latitude,
          longitude:p.coords.longitude
        };
        this.http.post('https://XXXXX/datacenteres.php', {
          dataObj
        })
          .subscribe(
            res => {
              console.log(res);
            },
            err => {
              console.log("Error occured");
            }
          );
      })
    }

Answer 3

Try like this :

use .bind(this) end of the function

ngOnInit(): void {
    if (navigator.geolocation) {
        navigator.geolocation.getCurrentPosition(function(p) {
            var LatLng = new google.maps.LatLng(p.coords.latitude, p.coords.longitude);

            console.log(p.coords.latitude);
            console.log(p.coords.longitude);

            var dataObj = {
                latitude: p.coords.latitude,
                longitude: p.coords.longitude
            };
            this.http.post('https://XXXXX/datacenteres.php', {
                dataObj
            }).subscribe(res => {
                console.log(res);
            }, err => {
                console.log("Error occured");
            });
        }.bind(this));

    }
}