welldone-software/why-did-you-render

Wdyr ignores equality function in useSelector

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Aperta il 16 apr 2021

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 (3 commenti) (1 reazione) (0 assegnatari)JavaScript (10.560 star) (188 fork)batch import
Low prioritybuggood first issuehelp wanted

Descrizione

When using wdyr I noticed that it reports unnecessary renders caused by useSelector with an equality function even though the equality function causes the render to be avoided. Looking at the code it looks like wdyr does not consider the result of the equality function.

An example:

useSelector(someSelector, (prev, next) => true);

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Tech stack
javascriptreact
Dominio
frontenddeveloper experience
Tipo issue
bug
DifficoltàQuanto dovrebbe essere impegnativa per un nuovo contributor.
3
Tempo stimatoTempo stimato per completare e verificare uno scope piccolo.
1-3 hours
Stato attivitàQuanto è probabile che la issue sia ancora attiva e reviewable.
stale
ChiarezzaQuanto chiaramente la issue descrive problema, scope e risultato atteso.
clear
Prerequisiti
React basicsunderstanding of useSelectorfamiliarity with wdyr
Adatta ai principiantiQuanto la issue è adatta a contributor alla prima esperienza.
60
Direzione di ricerca
Start by locating the code in the why did you render repository that tracks renders and detects unnecessary re renders. Specifically, look for how useSelector is patched and where the equality function is called. The issue suggests that the equality function's result is ignored. Investigate the patch logic in files like 'trackHooks.js' or similar. Check the existing comments and any linked PRs for additional context. Confirm that the equality function result is not considered and then implement a fix that respects it.