Run results for: Object.assign vs SPREAD

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:79.0) Gecko/20100101 Firefox/79.0

Browser: Firefox 79

Operating system: Mac OS X 10.15

Device Platform: Desktop

Date tested: 4 years ago

Test name	Executions per second
Object assign	20437.8 Ops/sec
SPREAD	12295.7 Ops/sec

Script Preparation code:

var foo = {};
for (var i=0;i<100;i++) {
    foo['foo'+i] = i;
    foo['foobar'+i] = i;
}

var bar = {};
for (var i=0;i<100;i++) {
    bar['bar'+i] = i;
    bar['foobar'+i] = i;
}

Tests:

Object assign
console.log(Object.assign({}, foo, bar));
SPREAD
console.log({...foo, ...bar});

Run results for: Object.assign vs SPREAD

Object assign

SPREAD