Run results for: Map vs Vanilla For vs For Of

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.142 Safari/537.36

Browser: Chrome 75

Operating system: Mac OS X 10.14.5

Device Platform: Desktop

Date tested: 4 years ago

Script Preparation code:

var objects = [{
  "key1": 'hello'
}, {
  "key2": 'bye'
}, {
  "key3": 'olleh'
}, {
  "key4": 'eyb'
}];

Tests:

Map with clone
objects.map((obj) => { obj = Object.assign({}, obj); obj.group = 'grouping'; return obj; })
Map
objects.map((obj) => { obj.group = 'grouping'; return obj; })
Vanilla For
for (let i = 0; i < objects.length; i++) { objects[i].group = 'grouping'; }
For Of
for (const obj of objects) { obj.group = 'grouping'; }