Using watchPosition with arrow function

Question

I'm using the following code to get a users location using watchPosition . I would also like to define code for the fail parameter and pass options to watchPosition , but I'm not sure where the code should go.

if (navigator.geolocation) {
      //Success callback defined, but where shouls fail & options go?
      var positionTimer = navigator.geolocation.watchPosition((position) => {
      var crd = position.coords;

      console.log("Updated user loc...");
      console.log(crd.latitude + " : " + crd.longitude);


      this.myLatitude = crd.latitude;
      this.myLongitude = crd.longitude;

      this.updateUserLocation();
    },
    console.warn("Error getting user location"),
    this.options);
}
else {
  alert("Geolocation not supported in your browser!");
}

Answer 1

Here's what you want:

const positionTimer = navigator.geolocation.watchPosition(
  (position) => {
    // Your success code here
    console.log(position);
  },
  (err) => {
    // Your error code here
    console.log(err);
  },
  {
    // Options here
  }
)

Just remember:

An arrow function expression has a shorter syntax than a function expression and does not bind its own this, arguments, super, or new.target. These function expressions are best suited for non-method functions, and they cannot be used as constructors.

Source: Arrow functions

You can use them just like you would use a normal function the things that change are just the mentioned above.

You could also declare your arrow functions:

const success = (position) => { /* Success code here */ }
const error = (err) => { /* Error code here */ }
const options = { /* Options... */ }

const positionTimer = navigator.geolocation.watchPosition(success, error, options);

Answer 2

Here you go:

 const options = {}; const id = navigator.geolocation.watchPosition((pos) => { console.log(pos); }, (err) => { console.log(err); }, options)