Only One Tab

Run a function in exactly one open tab, switching to another if closed.

Goals

• Robust across browsers
• Fully tested

Usage

const onlyOneTab = require('only-one-tab')

// only one daemon will run at a time across all tabs
onlyOneTab(() => {
  startDaemon()
})

API

onlyOneTab(cb)

The callback is run only once per tab, and on exactly one tab at a time. When the actor tab that ran the callback is closed, then exactly one other open tab runs its callback to replace it as the actor.

Recovery

After a browser crash, or something similar, the actor tab can be closed without being replaced normally.

Every tab periodically checks for an active tab's heartbeat, and after 1-4 seconds, a new tab will become the actor to replace the crashed tab. A refresh or new tab will do the check immediately on startup as well.

If nothing goes wrong, a new actor replaces the closed tab immediately.