Benchmark: Reduce and Spread vs. Foreach and Mutate

Script Preparation code:

var objectsArray = Array(1000).fill(() => {
  const key = Math.random().toString(36).substring(2, 5);
  const value = Math.random().toString(36).substring(2, 5);
  return {[key]: value};
});

Tests:

Reduce and Spread
var combined = objectsArray.reduce((memo, obj) => ({...memo, ...obj}), {});
ForEach and Mutate (for .. in loop)
var combined = {} objectsArray.forEach(obj => { for (key in obj) { combined[key] = obj[key]; } });
Mutate with Object.assign
var combined = Object.assign(...objectsArray)
Foreach and Mutate (Object.assign)
var combined = {} objectsArray.forEach(obj => Object.assign(combined, obj));

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Reduce and Spread
ForEach and Mutate (for .. in loop)
Mutate with Object.assign
Foreach and Mutate (Object.assign)

Fastest: N/A

Slowest: N/A

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Latest run results:

Run details: (Test run date: one month ago)

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/123.0.0.0 Safari/537.36

Browser/OS: Chrome 123 on Windows

View result in a separate tab

Test name	Executions per second
Reduce and Spread	100481.5 Ops/sec
ForEach and Mutate (for .. in loop)	319679.4 Ops/sec
Mutate with Object.assign	227602.6 Ops/sec
Foreach and Mutate (Object.assign)	18539.6 Ops/sec

Reduce and Spread vs. Foreach and Mutate (version: 0)

Comparing performance of: Reduce and Spread vs ForEach and Mutate (for .. in loop) vs Mutate with Object.assign vs Foreach and Mutate (Object.assign)

Created: 3 years ago by: Guest

Jump to the latest result

Reduce and Spread

ForEach and Mutate (for .. in loop)

Mutate with Object.assign

Foreach and Mutate (Object.assign)

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A