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packages/runtime-dom/src/modules/events.ts (1)

122-133: ⚡ Quick win

Avoid per-handler args-array allocations in the hot loop.

This path still allocates [e] for every handler invocation. Hoist it once per dispatch to keep the allocation reduction goal intact.

♻️ Proposed fix

     if (isArray(value)) {
       const originalStop = e.stopImmediatePropagation
       e.stopImmediatePropagation = () => {
         originalStop.call(e)
         ;(e as any)._stopped = true
       }
+      const args = [e]
       for (let i = 0; i < value.length; i++) {
         if ((e as any)._stopped) {
           break
         }
         const handler = value[i]
         if (handler) {
           callWithAsyncErrorHandling(
             handler,
             instance,
             ErrorCodes.NATIVE_EVENT_HANDLER,
-            [e],
+            args,
           )
         }
       }
     } else {

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@packages/runtime-dom/src/modules/events.ts` around lines 122 - 133, The
hot-loop currently allocates a new args array for every handler call by passing
[e] inline; hoist that allocation out of the loop by creating a single const
args = [e] immediately before the for loop and pass args into
callWithAsyncErrorHandling instead. Update the loop in events.ts where value
(the handlers array) is iterated and ensure callWithAsyncErrorHandling(handler,
instance, ErrorCodes.NATIVE_EVENT_HANDLER, args) is used so no per-handler array
allocations occur.

packages/runtime-dom/__benchmarks__/events.bench.ts (1)

5-22: ⚡ Quick win

Benchmark body currently mixes setup cost with dispatch cost.

Given the bench names, consider moving createElement + patchProp setup outside the timed callback so the metric isolates dispatch performance.

📊 Proposed refactor

 describe('runtime-dom events', () => {
+  const singleEl = document.createElement('button')
+  let singleCount = 0
+  patchProp(singleEl, 'onClick', null, () => singleCount++)
+
+  const multiEl = document.createElement('button')
+  let multiCount = 0
+  patchProp(multiEl, 'onClick', null, [
+    () => multiCount++,
+    () => multiCount++,
+    () => multiCount++,
+    () => multiCount++,
+  ])
+
   bench('dispatch click with single handler', () => {
-    const el = document.createElement('button')
-    let count = 0
-    patchProp(el, 'onClick', null, () => count++)
-    el.dispatchEvent(new Event('click'))
+    singleEl.dispatchEvent(new Event('click'))
   })
 
   bench('dispatch click with multiple handlers', () => {
-    const el = document.createElement('button')
-    let count = 0
-    patchProp(el, 'onClick', null, [
-      () => count++,
-      () => count++,
-      () => count++,
-      () => count++,
-    ])
-    el.dispatchEvent(new Event('click'))
+    multiEl.dispatchEvent(new Event('click'))
   })
 })

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@packages/runtime-dom/__benchmarks__/events.bench.ts` around lines 5 - 22, The
benchmark callbacks currently include setup (document.createElement + patchProp)
which contaminates dispatch timing; extract the setup for both benches so only
el.dispatchEvent(new Event('click')) runs inside each bench callback: create the
button element once per bench, call patchProp(el, 'onClick', null, ...)
beforehand (for the single-handler and the array-of-handlers cases), then have
the bench callback simply call el.dispatchEvent(...). Reference the existing
bench(...) invocations, document.createElement, patchProp, and el.dispatchEvent
when making the change.