Run results for: JavaScript Object.assign vs for in loop vs for of loop vs Object.entries

Run details:

User agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:108.0) Gecko/20100101 Firefox/108.0

Browser: Firefox 108

Operating system: Windows 8.1

Device Platform: Desktop

Date tested: one year ago

Tests:

Object.assign
const a = { x: 'xxx', y: 1, z: null } const b = { z: 1, u: 'uuu', v: null } Object.assign(a, b);
for in loop
const a = { x: 'xxx', y: 1, z: null } const b = { z: 1, u: 'uuu', v: null } for (const prop in b) { if (b.hasOwnProperty(prop)) { a[prop] = b[prop]; } }
for of loop
const a = { x: 'xxx', y: 1, z: null } const b = { z: 1, u: 'uuu', v: null } for (const prop of Object.keys(b)) { a[prop] = b[prop]; }
for Object entries
const a = { x: 'xxx', y: 1, z: null } const b = { z: 1, u: 'uuu', v: null } for (const [key, value] of Object.entries(b)) { a[key] = value; }
for in without check
const a = { x: 'xxx', y: 1, z: null } const b = { z: 1, u: 'uuu', v: null } for (const prop in b) { a[prop] = b[prop]; }