Benchmark: Build vs copy object

Script Preparation code:

keys = ["a", "b", "c", "d", "e", "f", "g", "h", "i", "j"];
values = [1, 2, 3, 4, 5, 6, 7, 9, 10];
templateObj = Object.fromEntries(keys.map(k => [k, undefined]));
pairs = keys.map((k, i) => [k, values[i]]);

Tests:

Build up object
const obj = {}; for (const [k, v] of pairs) { obj[k] = v; }
Use fromEntries
Object.fromEntries(pairs)
Copy and fill
const obj = {...templateObj}; for (const [k, v] of pairs) { obj[k] = v; }
Assign and fill
const obj = {}; Object.assign(obj, templateObj); for (const [k, v] of pairs) { obj[k] = v; }

Rendered benchmark preparation results:

Suite status: <idle, ready to run>

Previous results

Test case name	Result
Build up object
Use fromEntries
Copy and fill
Assign and fill

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 (Macintosh; Intel Mac OS X 10.15; rv:123.0) Gecko/20100101 Firefox/123.0

Browser/OS: Firefox 123 on Mac OS X 10.15

View result in a separate tab

Test name	Executions per second
Build up object	10228330.0 Ops/sec
Use fromEntries	3587368.0 Ops/sec
Copy and fill	5112843.0 Ops/sec
Assign and fill	8851860.0 Ops/sec

Build vs copy object (version: 0)

Is it faster to add properties to an object one by one, or create an object with all of them and set values one by one?

Comparing performance of: Build up object vs Use fromEntries vs Copy and fill vs Assign and fill

Created: one month ago by: Guest

Jump to the latest result

Build up object

Use fromEntries

Copy and fill

Assign and fill

Suite status: <idle, ready to run>

Experimental features:

Fastest: N/A

Slowest: N/A