solidjs / solid / 34440098982

72%

main: 89%

push

github

perf(web,signals): spread() reads a merge() proxy through its sources (#3325)

A spread mixed with other attributes compiles to `spread(el, merge(statics, () => rest))`. Going through the merge proxy cost merge's `keys()` (a Set plus an own-enumerable scan of every source) and then, per key, a right-to-left `in` walk of the sources, every run. The spread now iterates the flattened sources directly — own string keys, later sources overriding earlier, children/ref excluded — through the same single-trap `ownKeys` path readShallow() uses (#3326). omit() is not a merge and stays opaque.

mergeSources() answers only for merge()'s PROXY form: the plain-object form also records $SOURCES but is a real object callers mutate afterwards (@solidjs/html assigns props after spreading), so it is read directly.

readShallow() re-maps class arrays element-wise instead of copy-on-write (−58 B brotli on web.js; className allocates for an array anyway, paired bench at parity).

CodSpeed: spread merge(static, reactive) × 500 24.4 → 16.5 ms (+47.9%), store record +6.8%, 149 untouched. Local paired Tier-1: merge row 602 → 1,243 ops/s.

Co-authored-by: Cursor <cursoragent@cursor.com>

518 of 788 branches covered (65.74%)

Branch coverage included in aggregate %.

771 of 1006 relevant lines covered (76.64%)

15.0 hits per line