JS Geolocation API – getCurrentPosition with options parameter

In the last post (JS Geolocation API – Get a User's Location) we have covered navigator.geolocation.getCurrentPosition() method to get user's location. We have used the success and error callbacks to receive the position object or report error.

The method getCurrentPosition() also accepts an options object as third paramter (optional).

This options object allows you to specify:

• enableHighAccurancy (default false): if set to true, response is slower and more accurate.
• maximumAge (default 0): milliseconds when cached value is valid, the device may decide to use valid cached data instead of sensor measure. Represents age for the returned position value (up until this age it will be cached and reused if the same position is requested again, after this the browser will request fresh position data)
• timeout (default infinity): milliseconds before the API gives up and calls the error handler (the second parameter).

The example below calls getCurrentPosition() with both success and error callbacks, and pass the options object in third argument:

var options = {
  enableHighAccuracy: true,
  timeout: 5000, //timeout 5 seconds
  maximumAge: 10000 //(location) age 10 seconds
};

navigator.geolocation.getCurrentPosition(success, error, options);

Related Post(s):

• JS Geolocation API – Get a User's Location

JS Geolocation API – Get a User's Location

The JavaScript Geolocation API provides access to geographical location data associated with a user's device. This can be determined using GPS, WIFI, IP Geolocation and so on.

Geolocation is most accurate for devices with GPS, like smartphones.

To protect the user's privacy, it requests permission to locate the device. If the user grants permission, you will gain access to location data such as latitude, longitude, altitude and speed etc.

The Geolocation API is available through the navigator.geolocation object.

If the object exists, geolocation services are available. You can test for the presence of geolocation:

if ("geolocation" in navigator) {
  console.log("geolocation is available");
} else {
  console.log("geolocation is not available");
}

navigator.geolocation object provides the method getCurrentPosition() to return the user's position.

There are three possible arguments with this method:

• A success callback (required)
• An error callback (optional)
• An options object (optional)

The example below calls getCurrentPosition() with both success and error callbacks, and returns the latitude and longitude of the user's position:

function getLocation() {
  if (navigator.geolocation) {
    navigator.geolocation.getCurrentPosition(usePositionData, useError);
  } else {
    console.log("Geolocation is not supported by this browser.");
  }
}

function usePositionData(position) {
	//do something with position data.
	console.log("Latitude: " + position.coords.latitude);
	console.log("Longitude: " + position.coords.longitude);
}

function useError(error) {
  switch(error.code) {
    case error.PERMISSION_DENIED:
      console.log("User denied the request for Geolocation.");
      break;
    case error.POSITION_UNAVAILABLE:
      console.log("Location information is unavailable.");
      break;
    case error.TIMEOUT:
      console.log("The request to get user location timed out.");
      break;
    case error.UNKNOWN_ERROR:
      console.log("An unknown error occurred.");
      break;
  }
}

Related Post(s):

• JS Geolocation API – getCurrentPosition with options parameter