Run results for: deepmerge comparison

Run details:

User agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/138.0.0.0 Safari/537.36

Browser: Chrome 138

Operating system: Mac OS X 10.15.7

Device Platform: Desktop

Date tested: 9 months ago

Test name	Executions per second
lodash merge	602095.2 Ops/sec
object.assign	1420212.6 Ops/sec

HTML Preparation code:


<script src='https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.21/lodash.min.js'></script>
<script src='https://unpkg.com/deepmerge@4.3.1/dist/umd.js'></script>

Script Preparation code:

var a = {
  id: 1,
  name: "root",
  meta: {
    created: "2025-09-12",
    tags: ["alpha", "beta"],
    author: {
      name: "Alice",
      roles: ["admin", "editor"],
    },
    stats: {
      views: 100,
      likes: 10,
    }
  },
  settings: {
    theme: "light",
    notifications: {
      email: true,
      sms: false
    }
  }
};

var b = {
  meta: {
    tags: ["gamma"],
    author: {
      roles: ["viewer"],
      email: "alice@example.com"
    },
    stats: {
      likes: 25,
      shares: 5
    }
  },
  settings: {
    theme: "dark",
    notifications: {
      push: true
    }
  },
  extra: {
    nested: {
      deep: {
        value: 42
      }
    }
  }
};

Tests:

lodash merge
var c = _.merge({}, a, b);
deepmerge
var c = deepmerge({}, a, b);

Run results for: deepmerge comparison

lodash merge

deepmerge