Run results for: Merge objects comparison

Run details:

User agent: Mozilla/5.0 (iPhone; CPU iPhone OS 16_4 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/16.4 Mobile/15E148 Safari/604.1

Browser: Mobile Safari 16

Operating system: iOS 16.4

Device Platform: Mobile

Date tested: one year ago

Test name	Executions per second
Using Reduce ES5	5818620.5 Ops/sec
Using Reduce ES5 (test with `in`)	5535982.0 Ops/sec
Using Reduce ES5 (test with `hasOwnProperty`)	5410120.5 Ops/sec
Using Reduce ES6	3914781.8 Ops/sec
Using Reduce ES6 (test with `in`)	3762212.5 Ops/sec
Using Reduce ES6 (test with `hasOwnProperty`)	3709589.2 Ops/sec
Using For...	8271503.0 Ops/sec
Using For... In	28793102.0 Ops/sec
Using For... In (test with `in`)	14358598.0 Ops/sec
Using For... In (test with `hasOwnProperty`)	32081986.0 Ops/sec

Tests:

Using Reduce ES5
const firstObject = { a: 'Hello,', b: 'World' }; const secondObject = { b: 'World!', c: '!' }; const mergedObject = Object.keys(firstObject) .reduce(function(accumulator, key) { let toMerge = secondObject[key]; if (!toMerge) { toMerge = firstObject[key]; } accumulator[key] = toMerge; return accumulator; }, {});
Using Reduce ES5 (test with `in`)
const firstObject = { a: 'Hello,', b: 'World' }; const secondObject = { b: 'World!', c: '!' }; const mergedObject = Object.keys(firstObject) .reduce(function(accumulator, key) { accumulator[key] = firstObject[key]; if (key in secondObject) { accumulator[key] = secondObject[key]; } return accumulator; }, {});
Using Reduce ES5 (test with `hasOwnProperty`)
const firstObject = { a: 'Hello,', b: 'World' }; const secondObject = { b: 'World!', c: '!' }; const mergedObject = Object.keys(firstObject) .reduce(function(accumulator, key) { accumulator[key] = firstObject[key]; if (secondObject.hasOwnProperty(key)) { accumulator[key] = secondObject[key]; } return accumulator; }, {});
Using Reduce ES6
const firstObject = { a: 'Hello,', b: 'World' }; const secondObject = { b: 'World!', c: '!' }; const mergedObject = Object.keys(firstObject) .reduce((a, key) => { let toMerge = secondObject[key]; if (!toMerge) { toMerge = firstObject[key]; } return { ...a, [key]: toMerge}; }, {});
Using Reduce ES6 (test with `in`)
const firstObject = { a: 'Hello,', b: 'World' }; const secondObject = { b: 'World!', c: '!' }; const mergedObject = Object.keys(firstObject) .reduce((a, key) => { let toMerge = firstObject[key]; if (key in secondObject) { toMerge = secondObject[key]; } return { ...a, [key]: toMerge}; }, {});
Using Reduce ES6 (test with `hasOwnProperty`)
const firstObject = { a: 'Hello,', b: 'World' }; const secondObject = { b: 'World!', c: '!' }; const mergedObject = Object.keys(firstObject) .reduce((a, key) => { let toMerge = firstObject[key]; if (secondObject.hasOwnProperty(key)) { toMerge = secondObject[key]; } return { ...a, [key]: toMerge}; }, {});
Using For...
const firstObject = { a: 'Hello,', b: 'World' }; const secondObject = { b: 'World!', c: '!' }; let mergedObject = firstObject; const keys = Object.keys(mergedObject); for (let index = 0; index < keys.length; index++) { const key = keys[index]; if (secondObject[key]) { mergedObject[key] = secondObject[key]; } }
Using For... In
const firstObject = { a: 'Hello,', b: 'World' }; const secondObject = { b: 'World!', c: '!' }; let mergedObject = firstObject; for (let key in mergedObject) { if (secondObject[key]) { mergedObject[key] = secondObject[key]; } }
Using For... In (test with `in`)
const firstObject = { a: 'Hello,', b: 'World' }; const secondObject = { b: 'World!', c: '!' }; let mergedObject = firstObject; for (let key in mergedObject) { if (key in secondObject) { mergedObject[key] = secondObject[key]; } }
Using For... In (test with `hasOwnProperty`)
const firstObject = { a: 'Hello,', b: 'World' }; const secondObject = { b: 'World!', c: '!' }; let mergedObject = firstObject; for (let key in mergedObject) { if (secondObject.hasOwnProperty(key)) { mergedObject[key] = secondObject[key]; } }

Run results for: Merge objects comparison

Using Reduce ES5

Using Reduce ES5 (test with `in`)

Using Reduce ES5 (test with `hasOwnProperty`)

Using Reduce ES6

Using Reduce ES6 (test with `in`)

Using Reduce ES6 (test with `hasOwnProperty`)

Using For...

Using For... In

Using For... In (test with `in`)

Using For... In (test with `hasOwnProperty`)