41 lines
975 B
TypeScript
41 lines
975 B
TypeScript
// Copyright 2021 Signal Messenger, LLC
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// SPDX-License-Identifier: AGPL-3.0-only
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export function waitForOnline(
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navigator: Readonly<{ onLine: boolean }>,
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onlineEventTarget: EventTarget,
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options: Readonly<{ timeout?: number }> = {}
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): Promise<void> {
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const { timeout } = options;
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return new Promise((resolve, reject) => {
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if (navigator.onLine) {
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resolve();
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return;
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}
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let timeoutId: undefined | ReturnType<typeof setTimeout>;
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const listener = () => {
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cleanup();
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resolve();
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};
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const cleanup = () => {
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onlineEventTarget.removeEventListener('online', listener);
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if (typeof timeoutId === 'number') {
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clearTimeout(timeoutId);
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}
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};
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onlineEventTarget.addEventListener('online', listener);
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if (timeout !== undefined) {
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timeoutId = setTimeout(() => {
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cleanup();
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reject(new Error('waitForOnline: did not come online in time'));
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}, timeout);
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}
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});
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}
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