FIX extremely frequent getPinboardsByIds GraphQL calls
#152
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…seEffect oversight, combined with frequent re-renders) Co-Authored-By: Andrew Nowak <andrew.nowak@guardian.co.uk>
andrew-nowak
approved these changes
Aug 12, 2022
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Seen on PROD (merged by @twrichards 3 minutes and 14 seconds ago) Please check your changes! |
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Co-Authored-By: @andrew-nowak
When experimenting/working on #150 , @andrew-nowak astutely noticed a very high amount of AJAX requests in the Network tab of developer tools, specifically
getPinboardsByIdsGraphQL calls. We tracked this down to an oversight in our understanding of how the dependency list on React'suseEffecthook works, where it does reference checking not deep object/array equality, as such thegetPinboardsByIdsrefetch was being triggered (in thatuseEffectblock) when ever theactivePinboardIdsarray reference was being updated (which was happening very frequently) even though the values we not changing - the solution we found online was toJSON.stringifyto make the value stable, however we found that spreading theactivePinboardIdsarray into the dependency list had the same effect and was more elegant (and probably cheaper too).Whilst there we also noticed a possible cause of unnecessary re-renders (although probably unrelated to this issue), which we've hopefully addressed by the change detection we've added before setting state relating to stuff detected in the DOM of the host application (e.g. the preselected pinboard ID put there by composer).