Benchmark: JavaScript filter vs reduce

Tests:

Using array filter and reduce + spread
PRIMARY_SCOPES = ['a', 'd'] availableScopes = {'a': 'A', 'b': 'B', 'c': 'C', 'd': 'D'} const output = PRIMARY_SCOPES.filter((scope) => scope in availableScopes).reduce( (result, scope) => ({ ...result, [scope]: availableScopes[scope], }), {}, );
Using array filter and object assign
PRIMARY_SCOPES = ['a', 'd'] availableScopes = {'a': 'A', 'b': 'B', 'c': 'C', 'd': 'D'} const output = {}; Object.entries(availableScopes).forEach(([key, value]) => { if (!PRIMARY_SCOPES.includes(key)) { return; } Object.assign(output, { [key]: value }); }); return output;

Rendered benchmark preparation results:

Previous results

Test case name	Result
Using array filter and reduce + spread
Using array filter and object assign

ⓘ Get performance results from real users on your website with Request Metrics.

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/112.0.0.0 Safari/537.36

Browser/OS: Chrome 112 on Mac OS X 10.15.7

Test name	Executions per second
Using array filter and reduce + spread	1013945.0 Ops/sec
Using array filter and object assign	810108.6 Ops/sec

JavaScript filter vs reduce (version: 0)