ebd10a43d2
* perf: fetch lists from database on page load follow-up to #1448, I would like for there not to be a flash on the /community page where the lists suddenly load in, but I would still like to avoid the network request if possible. So when the page first loads, we can load the lists from the database and only fetch them from the network if not in the cache. * add comment
40 lines
1.4 KiB
JavaScript
40 lines
1.4 KiB
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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const 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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} catch (err) {
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console.error('ignored DB error', err)
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} finally {
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if (dbResponse) {
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stateSetter(dbResponse)
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}
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const 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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// Try the cache first. If we get a hit, set the state and do nothing. If we don't get a cache hit,
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// then go to the network, update the cache, and set the state.
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export async function cacheFirstUpdateOnlyIfNotInCache (networkFetcher, dbFetcher, dbUpdater, stateSetter) {
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let dbResponse
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try {
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dbResponse = await dbFetcher()
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} catch (err) {
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console.error('ignored DB error', err)
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}
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if (dbResponse) {
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stateSetter(dbResponse)
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} else {
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const networkResponse = await networkFetcher()
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/* no await */ dbUpdater(networkResponse)
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stateSetter(networkResponse)
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}
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}
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