63 lines
1.4 KiB
JavaScript
63 lines
1.4 KiB
JavaScript
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// @flow
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/**
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* SET_INTERVAL constant is used to set interval and it is set in
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* the id property of the request.data property. timeMs property must
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* also be set. request.data example:
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*
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* {
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* id: SET_INTERVAL,
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* timeMs: 33
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* }
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*/
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export const SET_INTERVAL = 1;
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/**
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* CLEAR_INTERVAL constant is used to clear the interval and it is set in
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* the id property of the request.data property.
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*
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* {
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* id: CLEAR_INTERVAL
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* }
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*/
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export const CLEAR_INTERVAL = 2;
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/**
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* INTERVAL_TIMEOUT constant is used as response and it is set in the id
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* property.
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*
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* {
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* id: INTERVAL_TIMEOUT
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* }
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*/
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export const INTERVAL_TIMEOUT = 3;
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/**
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* The following code is needed as string to create a URL from a Blob.
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* The URL is then passed to a WebWorker. Reason for this is to enable
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* use of setInterval that is not throttled when tab is inactive.
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*/
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const code = `
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var timer;
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onmessage = function(request) {
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switch (request.data.id) {
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case ${SET_INTERVAL}: {
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timer = setInterval(() => {
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postMessage({ id: ${INTERVAL_TIMEOUT} });
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}, request.data.timeMs);
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break;
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}
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case ${CLEAR_INTERVAL}: {
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if (timer) {
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clearInterval(timer);
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}
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break;
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}
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}
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};
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`;
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export const timerWorkerScript
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= URL.createObjectURL(new Blob([ code ], { type: 'application/javascript' }));
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