18 lines
736 B
JavaScript
18 lines
736 B
JavaScript
// Hit both the cache and the network, setting state for the cached version first,
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// then the network version (as it's assumed to be fresher). Also update the db afterwards.
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export async function cacheFirstUpdateAfter (networkFetcher, dbFetcher, dbUpdater, stateSetter) {
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let networkPromise = networkFetcher() // kick off network request immediately
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let dbResponse
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try {
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dbResponse = await dbFetcher()
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stateSetter(dbResponse)
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} finally {
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let fetchAndUpdatePromise = networkPromise.then(networkResponse => {
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/* no await */ dbUpdater(networkResponse)
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stateSetter(networkResponse)
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})
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if (!dbResponse) { // no cached result available, await the network
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await fetchAndUpdatePromise
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}
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}
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}
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