Run results for: JavaScript filter vs reduce

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/15.4 Safari/605.1.15

Browser: Safari 15

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
Using array filter and reduce + spread	781301.0 Ops/sec
Using array filter and object assign	413650.4 Ops/sec

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;