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josephsavona
aa31ab17b8
`@enablePreserveExistingMemoizationGuarantees` mode currently does not
guarantee memoization of primitive-returning functions. We're often able
to infer that a function returns a primitive based on how its result is
used, for example `foo() + 1` or `object[getIndex()]`, and by default we
do not currently memoize computation that produces a primitive. The
reasoning behind this is that the compiler is primarily focused on
stopping cascading updates — it's fine to recompute a primitive since we
can cheaply compare that primitive and avoid unnecessary downstream
recomputation. But we've gotten a lot of feedback that people find this
surprising, and that sometimes the computation can be expensive enough
that it should be memoized.
This PR changes `@enablePreserveExistingMemoizationGuarantees` mode to
ensure that primitive-returning functions get memoized. Other modes will
not memoize these functions. Separately from this we are considering
enabling this mode by default.
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[//]: # (BEGIN SAPLING FOOTER)
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* #34347
* #34346
* __->__ #34343
* #34335
DiffTrain build for [735e9ac54e](https://github.com/facebook/react/commit/735e9ac54e5b46e5a963e0e436330baf20fb04c2)