←  main.js
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The client code
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When adding the script offliner-client.js, the module off is exported. If you find this collisions with one of your modules, call off.restore().
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Calling .on() you can start listening for some events. This case, the event activationPending is triggered each time an update is completed to leave the client the responsibility of switching to the new version.

 
off.on('activationPending', function () {
  var confirmation = confirm('There is a new version available. ' +
                             'Do you want to update?');
  if (confirmation) {
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Calling activate() you ask offliner to switch to the cache containing the new version. Commonly, the client reloads after activating.

 
    off.activate().then(function (v) {
      alert('Updated to version ' + v + '\nReloading.');
      window.location = window.location;
    })
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The activate() call can fail if there is no need for update. In this case the reject handler is passed with 'no-activation-pending'.

 
    .catch(
      console.warn.bind(console, 'There was an error activating the update')
    );
  }
});
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Now install the worker and once installed, program periodic updates.

 
off.install().then(function () {
  if (!navigator.serviceWorker.controller) {
  }
  checkUpdate();
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An update check will be performed every minute.

 
  setInterval(checkUpdate, 60000);
});

function checkUpdate() {
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You call update() so offliner starts by checking if there is an update. If so, it downloads the new version and install it without switching to it, this switching is called activation.

 
  off.update()
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If the update process concludes properly, the promise Resolves to the new version.

 
    .then(function (v) {
      alert('New version ' + v + ' ready to be installed.');
    })
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If there is a failure or if there is no new version, the promise rejects. The reason passed will be 'no-update-needed'.

 
    .catch(
      console.log.bind(console, 'No new version available...')
    );
}