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A React Hook to determine if a tab of your application is the "leader" using BroadcastChannel and leader election
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import { BroadcastChannel, createLeaderElection } from 'broadcast-channel' | |
import React from 'react' | |
const channels = {} | |
export function useBroadcastLeader(id = 'default') { | |
const [isBroadcastLeader, setIsBroadcastLeader] = React.useState(false) | |
React.useEffect(() => { | |
if (!channels[id]) { | |
const channel = new BroadcastChannel('useBroadcastLeader_' + id) | |
const elector = createLeaderElection(channel) | |
channels[id] = { | |
channel, | |
elector, | |
subscribers: [], | |
} | |
elector.awaitLeadership().then(() => { | |
channels[id].subscribers.forEach(sub => { | |
sub(true) | |
}) | |
}) | |
} | |
channels[id].subscribers.push(setIsBroadcastLeader) | |
return () => { | |
channels[id].subscribers = channels[id].subscribers.filter( | |
d => d !== setIsBroadcastLeader | |
) | |
if (!channels[id].subscribers.length) { | |
channels[id].elector.die() | |
channels[id].channel.close() | |
delete channels[id] | |
} | |
} | |
}, [id]) | |
const waitForBroadcastLeader = React.useCallback( | |
() => channels[id].awaitLeadership(), | |
[id] | |
) | |
return { | |
isBroadcastLeader, | |
waitForBroadcastLeader, | |
} | |
} |
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