34 lines
1.2 KiB
JavaScript
34 lines
1.2 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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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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// Make a change that we optimistically show to the user as successful, but which
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// actually depends on a network operation. In the unlikely event that the network
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// operation fails, revert the changes
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export async function optimisticUpdate (doImmediately, networkUpdater, onSuccess, onFailure) {
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let networkPromise = networkUpdater()
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doImmediately()
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try {
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let response = await networkPromise
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onSuccess(response)
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} catch (e) {
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console.error(e)
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onFailure(e)
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}
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}
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