Run results for: Object assign vs direct assignment by iterating keys and assigning

Run details:

User agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.116 Safari/537.36

Browser: Chrome 83

Operating system: Linux

Device Platform: Desktop

Date tested: 3 years ago

Test name	Executions per second
With Object.assign()	1026061.0 Ops/sec
With Iteration and Assignment	1870058.0 Ops/sec
With Iteration and .keys().forEach	1601309.0 Ops/sec

Tests:

With Object.assign()
var toSave = { "def":100101102, "ghi":null, "jkl":106107108, "mno":109110111.106107108, "pqr":'112113114', "stu":NaN, "vwx":118119120, "yz{":[ { "vwx":118119120 }, { "vwx":118119120 } ], }; var dest = { "abc":979899 }; if (toSave) { Object.assign(dest, toSave); }
With Iteration and Assignment
var toSave = { "def":100101102, "ghi":null, "jkl":106107108, "mno":109110111.106107108, "pqr":'112113114', "stu":NaN, "vwx":118119120, "yz{":[ { "vwx":118119120 }, { "vwx":118119120 } ], }; var dest = { "abc":979899 }; if (toSave) { var keys = Object.keys(dest); for (var i = 0; i < keys.length; i++) { dest[keys[i]] = toSave[keys[i]]; } }
With Iteration and .keys().forEach
var toSave = { "def":100101102, "ghi":null, "jkl":106107108, "mno":109110111.106107108, "pqr":'112113114', "stu":NaN, "vwx":118119120, "yz{":[ { "vwx":118119120 }, { "vwx":118119120 } ], }; var dest = { "abc":979899 }; if (toSave) { var keys = Object.keys(dest).forEach(key => { dest[key] = toSave[key]; }); }