59 lines
1.4 KiB
TypeScript
59 lines
1.4 KiB
TypeScript
import { type Signal, useComputed, useSignal } from '@preact/signals'
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import { useEffect } from 'preact/hooks'
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type NetworkConnection = {
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addEventListener: (
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type: 'change',
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listener: (event: Event) => void | Promise<void>,
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) => void
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}
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declare global {
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interface Navigator {
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connection?: NetworkConnection
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}
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}
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export default function IsOnline(
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{ online, offline }: { online?: string; offline: string },
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) {
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const status = useSignal(true)
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const displayed = useComputed(() => {
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if (status.value && online) {
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return <span>{online}</span>
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}
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if (status.value) {
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return <span style={{ display: 'none' }}></span>
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}
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return <span class='island__is_online'>{offline}</span>
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})
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useEffect(() => {
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openSocket(status)
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navigator.connection?.addEventListener('change', () => {
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fetch('/api/serviceworker/is-online')
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.then(() => status.value = true)
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.catch(() => status.value = false)
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})
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}, [])
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return <>{displayed}</>
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}
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function openSocket(status: Signal<boolean>, timeout = 5_000) {
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const socket = new WebSocket(
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`wss://${location.host}/api/serviceworker/is-online`,
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)
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setTimeout(() => {
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if (socket.OPEN || socket.CONNECTING) return
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socket.close()
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}, timeout)
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socket.addEventListener('open', () => status.value = true)
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socket.addEventListener('close', () => {
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status.value = false
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setTimeout(() => openSocket(status), timeout)
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})
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}
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