Run results for: assign vs ...

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.0.0 Safari/537.36

Browser: Chrome 103

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 2 years ago

Test name	Executions per second
clone: assign	45904.8 Ops/sec
clone: ...	57669.6 Ops/sec
modify: assign	50176.0 Ops/sec
reassign: ...	12347.3 Ops/sec
clone: ... with first {}	56546.7 Ops/sec
reassign: ... with first {}	49032.2 Ops/sec

Tests:

clone: assign
const empty = {}; const n = 30; const obj1 = {}; for(let i = 0; i < n; i++) obj1[`o1-${i}`] = i; const obj1_1 = {}; for(let i = 0; i < n; i++) obj1_1[`o1-${i}`] = i; const obj2 = {}; for(let i = 0; i < n; i++) obj2[`o2-${i}`] = i; const obj3 = {}; for(let i = 0; i < n; i++) obj3[`o3-${i}`] = i; const a = Object.assign({}, obj1, obj2, obj3);
clone: ...
const empty = {}; const n = 30; const obj1 = {}; for(let i = 0; i < n; i++) obj1[`o1-${i}`] = i; const obj1_1 = {}; for(let i = 0; i < n; i++) obj1_1[`o1-${i}`] = i; const obj2 = {}; for(let i = 0; i < n; i++) obj2[`o2-${i}`] = i; const obj3 = {}; for(let i = 0; i < n; i++) obj3[`o3-${i}`] = i; const a = { ...obj1, ...obj2, ...obj3 };
modify: assign
const empty = {}; const n = 30; const obj1 = {}; for(let i = 0; i < n; i++) obj1[`o1-${i}`] = i; const obj1_1 = {}; for(let i = 0; i < n; i++) obj1_1[`o1-${i}`] = i; const obj2 = {}; for(let i = 0; i < n; i++) obj2[`o2-${i}`] = i; const obj3 = {}; for(let i = 0; i < n; i++) obj3[`o3-${i}`] = i; const o = JSON.parse(JSON.stringify(obj1_1)); Object.assign(o, obj1, obj2, obj3);
reassign: ...
const empty = {}; const n = 30; const obj1 = {}; for(let i = 0; i < n; i++) obj1[`o1-${i}`] = i; const obj1_1 = {}; for(let i = 0; i < n; i++) obj1_1[`o1-${i}`] = i; const obj2 = {}; for(let i = 0; i < n; i++) obj2[`o2-${i}`] = i; const obj3 = {}; for(let i = 0; i < n; i++) obj3[`o3-${i}`] = i; let o = JSON.parse(JSON.stringify(obj1_1)); o = { ...o, ...obj1, ...obj2, ...obj3 };
clone: ... with first {}
const empty = {}; const n = 30; const obj1 = {}; for(let i = 0; i < n; i++) obj1[`o1-${i}`] = i; const obj1_1 = {}; for(let i = 0; i < n; i++) obj1_1[`o1-${i}`] = i; const obj2 = {}; for(let i = 0; i < n; i++) obj2[`o2-${i}`] = i; const obj3 = {}; for(let i = 0; i < n; i++) obj3[`o3-${i}`] = i; const a = { ...{}, ...obj1, ...obj2, ...obj3 };
reassign: ... with first {}
const empty = {}; const n = 30; const obj1 = {}; for(let i = 0; i < n; i++) obj1[`o1-${i}`] = i; const obj1_1 = {}; for(let i = 0; i < n; i++) obj1_1[`o1-${i}`] = i; const obj2 = {}; for(let i = 0; i < n; i++) obj2[`o2-${i}`] = i; const obj3 = {}; for(let i = 0; i < n; i++) obj3[`o3-${i}`] = i; let o = JSON.parse(JSON.stringify(obj1_1)); o = { ...{}, ...o, ...obj1, ...obj2, ...obj3 };

Run results for: assign vs ...

clone: assign

clone: ...

modify: assign

reassign: ...

clone: ... with first {}

reassign: ... with first {}