Network Information API: How to Access Network Connection Speed Info

The Network Information API provides information about the system's
connection in terms of general connection type (e.g., 'wifi', 'cellular', etc.). This can be used to select high definition content or low definition content based on the user's connection. The entire API consists of the addition of the

NetworkInformation

interface and a single property to the

Navigator

interface:

Navigator.connection

.

This example watches for changes to the user's connection.

var connection = navigator.connection || navigator.mozConnection || navigator.webkitConnection;
var type = connection.effectiveType;

function updateConnectionStatus() {
  console.log("Connection type changed from " + type + " to " + connection.effectiveType);
  type = connection.effectiveType;
}

connection.addEventListener('change', updateConnectionStatus);

Preload large resources

The connection object is useful for deciding whether to preload resources that take large amounts of bandwidth or memory. This example would be called soon after page load to check for a connection type where preloading a video may not be desirable. If a cellular connection is found, then the

preloadVideo

flag is set to false. For simplicity and clarity, this example only tests for one connection type. A real-world use case would likely use a switch statement or some other method to check all of the possible values of

NetworkInformation.type

. Regardless of the type value you can get an estimate of connection speed through the

NetworkInformation.effectiveType

property.

let preloadVideo = true;
var connection = navigator.connection || navigator.mozConnection || navigator.webkitConnection;
if (connection) {
  if (connection.effectiveType=== 'cellular') {
    preloadVideo = false;
  }
}

NetworkInformation

Provides information about the connection a device is using to communicate with the network and provides a means for scripts to be
notified if the connection type changes. The

NetworkInformation

interfaces cannot be instantiated. It is instead accessed through the

Navigator

interface.