chrome extension first run

Question

Hi,

How can I find out if my extension is being run for the first time / has just been upgraded?

Thanks!

Answer 1

Simple. When the extension first runs, the localStorage is empty. On first run, you can write a flag there to mark all consequent runs as non-first.

Example, in background.htm:

var first_run = false;
if (!localStorage['ran_before']) {
  first_run = true;
  localStorage['ran_before'] = '1';
}

if (first_run) alert('This is the first run!');

EDIT: To check whether the extension has just been updated, store the version instead of a simple flag on first run, then when the current extension version (get it by XmlHttpRequesting the manifest) doesn't equal the one stored in localStorage, the extension has been updated.

Answer 2

If you want to check if the extension has been installed or updated, you can do something like this:

  function onInstall() {
    console.log("Extension Installed");
  }

  function onUpdate() {
    console.log("Extension Updated");
  }

  function getVersion() {
    var version = 'NaN';
    var xhr = new XMLHttpRequest();
    xhr.open('GET', chrome.extension.getURL('manifest.json'), false);
    xhr.send(null);
    var manifest = JSON.parse(xhr.responseText);
    return manifest.version;
  }

  // Check if the version has changed.
  var currVersion = getVersion();
  var prevVersion = localStorage['version']
  if (currVersion != prevVersion) {
    // Check if we just installed this extension.
    if (typeof prevVersion == 'undefined') {
      onInstall();
    } else {
      onUpdate();
    }
    localStorage['version'] = currVersion;
  }