Benchmark: flatmap vs reduce to filter undefined elements

Script Preparation code:

const myArray = [];

for (let i = 0; i < 10000; i++) {
  const obj = {
    prop1: `value${i}_1`,
    prop2: `value${i}_2`,
    prop3: `value${i}_3`,
    prop4: `value${i}_4`,
  };

  // Randomly add the metadata property
  if (Math.random() < 0.5) {
    obj.metadata = {
      info1: `metadata${i}_1`,
      info2: `metadata${i}_2`,
    };
  }

  myArray.push(obj);
}

Tests:

flatMap
myArray.flatMap(obj => { if (obj.metadata) { return { prop1: obj.prop1, metadata: obj.metadata }; } else { return []; } })
reduce
myArray.reduce((acc, obj) => { if (obj.metadata) { acc.push({ prop1: obj.prop1, metadata: obj.metadata }); } return acc; }, []);

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
flatMap
reduce

Fastest: N/A

Slowest: N/A

Latest run results:

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

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36

Browser/OS: Chrome 131 on Mac OS X 10.15.7

View result in a separate tab

reduce

12K/s

flatMap

7K/s

View exact numbers

Test name	Executions per second
✓ reduce	11,530 Ops/sec
flatMap	6,599 Ops/sec

flatmap vs reduce to filter undefined elements (version: 1)

Comparing performance of: `flatMap vs reduce`

Created: one year ago by: Guest

Go to the latest result

flatMap

reduce

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

flatmap vs reduce to filter undefined elements (version: 1)

Comparing performance of: flatMap vs reduce

Created: one year ago by: Guest

Go to the latest result

flatMap

reduce

Suite status: <idle, ready to run>

Fastest: N/A

Slowest: N/A

Related benchmarks

Comparing performance of: `flatMap vs reduce`