perf(utils): optimized reducer to avoid creating new objects (#8818)

Author: Connormiha

packages/vitest/src/utils/serialization.ts

@@ -3,11 +3,11 @@
 function cloneByOwnProperties(value: any) {
  // Clones the value's properties into a new Object. The simpler approach of
  // Object.assign() won't work in the case that properties are not enumerable.
- return Object.getOwnPropertyNames(value).reduce(
- (clone, prop) => ({
- ...clone,
- [prop]: value[prop],
- }),
+ return Object.getOwnPropertyNames(value).reduce<Record<string, any>>(
+ (clone, prop) => {
+ clone[prop] = value[prop]
+ return clone
+ },
  {},
  )
 }