Run results for: Map from .reduce vs Map from .map vs Map from generator function

Run details:

User agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:135.0) Gecko/20100101 Firefox/135.0

Browser: Firefox 135

Operating system: Windows

Device Platform: Desktop

Date tested: one year ago

Benchmark engine: Benchmark.js

Map from .reduce

4K/s

Map from .map

2K/s

Map from generator function

1K/s

View exact numbers

Test name	Executions per second
✓ Map from .reduce	3,587 Ops/sec
Map from .map	2,369 Ops/sec
Map from generator function	1,414 Ops/sec

Script Preparation code:

var arr10k = Array.from(Array(10000)).map((x, i) => ({ x1: i, x2: i * 2, x4: i * 4 }));

function* getItems() {
    for (const x of arr10k) {
        yield [x.x1, x];
    }
}

Tests:

Map from .reduce
arr10k.reduce((acc, x) => acc.set(x.x1, x), new Map());
Map from .map
new Map(arr10k.map(x => [x.x1, x]));
Map from generator function
new Map(getItems());