feat: optimize object property mutations in compilation #11243
Merged
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Currently, when compiling Svelte code containing object property mutations such as
object.count++
, the Svelte compiler generates verbose JavaScript output involving a closure and unnecessary variable assignment, as demonstrated in the example provided. This PR addresses this inefficiency by optimizing the generated JavaScript output for object property mutations.During my investigation, I observed that earlier versions of Svelte utilized the
mutate
function for updating values, which returned the value after modification. Consequently, logic akin to the current compiler-generated output was implemented. However, with the new Svelte version, this output is unnecessary, as simple expressions likeobject.count++
orobject.count += 1
suffice.The proposed solution involves enhancing the compiler to detect object property mutations and generate streamlined JavaScript output directly corresponding to the intended operation, without the need for additional closures or variable assignments. To achieve this, the compiler now checks the context when converting the code, specifically for the usage of
runes
.Closes #10546
Before submitting the PR, please make sure you do the following
feat:
,fix:
,chore:
, ordocs:
.Tests and linting
pnpm test
and lint the project withpnpm lint