Run results for: lodash merge vs asign

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_14_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.121 Safari/537.36

Browser: Chrome 72

Operating system: Mac OS X 10.14.3

Device Platform: Desktop

Date tested: 5 years ago

Test name	Executions per second
lodash merge	4170.9 Ops/sec
spread	43322.2 Ops/sec
for in	12065.0 Ops/sec

HTML Preparation code:


<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.min.js'></script>

Script Preparation code:

let data = {}
for (i = 0; i < 200; i++) {
  const sub = { x: 9, y: 8, z: 7 }
  data[i] = { 
    a: 1, 
    b: 2, 
    c: {
      x: 9, 
      y: 8, 
      z: 7
    }
  }
}
window.data = data

let newData = {}
for (i = 0; i < 100; i++) {
  const sub = { x: 9, y: 8, z: 7 }
  newData[i] = { 
    a: 0, 
    b: 0, 
    c: {
      x: 0, 
      y: 0, 
      z: 0
    }
  }
}
window.newData = newData

Tests:

lodash merge
var c = _.merge(window.data, window.newData);
spread
var c = { ...window.data, ...window.newData };
for in
let clone = Object.assign({}, window.newData) Object.keys(window.data).forEach(key => clone[key] = window.newData[key])

Run results for: lodash merge vs asign

lodash merge

spread

for in