tabs.discard()

Discards one or more tabs.

Some browsers automatically "discard" tabs that they don't think are likely to be needed by the user soon. The tab stays visible in the tabstrip and the browser remembers its state, so if the user selects a tab that has been discarded, it is immediately restored.

The details of exactly what is discarded are browser-specific, but in general, discarding a tab enables the browser to free some of the memory occupied by that tab.

The tabs.discard() API enables an extension to discard one or more tabs. It's not possible to discard the currently active tab, or a tab whose document contains a beforeunload listener that would display a prompt.

This is an asynchronous function that returns a Promise.

tabIds

integer or array of integer. The IDs of the tab or tabs to discard.

A Promise that will be fulfilled with no arguments when all the specified tabs have been discarded. If any error occurs (for example, invalid tab IDs), the promise will be rejected with an error message.

If the ID of the active tab is passed in, it will not be discarded, but the promise will be fulfilled and any other tabs passed in will be discarded.

Discard a single tab:

function onDiscarded() {
  console.log(`Discarded`);
}

function onError(error) {
  console.log(`Error: ${error}`);
}

let discarding = browser.tabs.discard(2);
discarding.then(onDiscarded, onError);

Discard multiple tabs:

function onDiscarded() {
  console.log(`Discarded`);
}

function onError(error) {
  console.log(`Error: ${error}`);
}

let discarding = browser.tabs.discard([15, 14, 1]);
discarding.then(onDiscarded, onError);