Lodash _.mixin() Method

Beginner
5 min read
Updated: Nov 2026
4 examples
Util
Decorative image with the word MIXIN

Definition

Adds all own enumerable string-keyed function properties of source to the destination object (defaults to Lodash). If the destination is a function, methods are added to its prototype as well. Part of Lodash Util since 0.1.0 (stable — not deprecated).

Pass the arguments shown below. Prefer modular imports when you only need this helper.

Syntax

Call _.mixin. Start with this line.

Lodash
_.mixin([object=lodash], source, [options={}])
CallWhat it does
_.mixin([object=lodash], source, [options={}])Primary signature.
_.mixin(...)Call the util helper.

Prefer import mixin from "lodash/mixin" when you want a smaller bundle.

Library declarations
Lodash
_.mixin([object=lodash], source, [options={}])

Parameters

ParameterDescription
objectOptional. Destination (default: Lodash). Functions also get prototype methods.
sourceRequired. Object whose own function properties are copied
options.chainOptional. Default true — keep mixins chainable

Return Value

Return ValueDescription
*The destination object

Lodash Examples

Example 1 — Official: vowels Mixin

Add a custom helper and call it directly or through a chain.

Lodash
function vowels(string) {
  return _.filter(string, function (v) {
    return /[aeiouy]/i.test(v);
  });
}

_.mixin({ 'vowels': vowels });

_.vowels('fred');
// → ['e']

_('fred').vowels().value();
// → ['e']
Try It Yourself

How It Works

  1. Define. vowels keeps letters that match the vowel regex.
  2. Mixin. _.mixin({ vowels }) attaches it to Lodash.
  3. Direct call. _.vowels('fred') → ['e'].
  4. Chain. With default chain: true, unwrap with .value().

Example 2 — chain: false

Disable chaining so a wrapped call returns the raw value.

Lodash
function vowels(string) {
  return _.filter(string, function (v) {
    return /[aeiouy]/i.test(v);
  });
}

_.mixin({ 'vowels': vowels }, { 'chain': false });

_('fred').vowels();
// → ['e']  (already unwrapped — no .value())
Try It Yourself

How It Works

  1. Same helper. Still filters vowels from the string.
  2. Option. { chain: false } marks the mixin non-chainable.
  3. Unwrap. _('fred').vowels() returns ['e'] directly.
  4. Use. Prefer this when the next step needs a plain array, not a wrapper.

Example 3 — Custom Destination Object

Extend your own utils object instead of the global _.

Lodash
var appUtils = {};

_.mixin(appUtils, {
  greet: function (name) {
    return 'Hello, ' + name + '!';
  }
});

appUtils.greet('Ada');
// → 'Hello, Ada!'
Try It Yourself

How It Works

  1. Target. First argument is appUtils, not Lodash.
  2. Copy. Own function greet is added to that object.
  3. Call. Use appUtils.greet(...) — _ stays untouched.
  4. Return. _.mixin returns appUtils for further chaining if needed.

Example 4 — Isolate with runInContext

Extend a private Lodash copy so the global _ stays clean.

Lodash
var lodash = _.runInContext();

lodash.mixin({
  double: function (n) {
    return n * 2;
  }
});

lodash.double(21);
// → 42

typeof _.double;
// → 'undefined'  (global _ was not mixed)
Try It Yourself

How It Works

  1. Fresh copy. _.runInContext() returns a private Lodash.
  2. Mixin there. double lives only on that copy.
  3. Call. lodash.double(21) → 42.
  4. Safe. Global _ has no double — avoids plugin clashes.
Compatibility

Browser & Runtime Support

_.mixin is a Lodash Util helper since 0.1.0. It runs anywhere the full Lodash build runs — modern browsers (CDN or bundle) and Node.js / Bun / Deno with npm install lodash.

✓ Stable · Lodash 0.1.0+

_.mixin()

Available in [email protected] full builds. Modular per-method imports do not include mixin alone — use the full build or a custom Lodash build when you need it.

100% With Lodash 0.1+
Google Chrome Supported · Desktop & Mobile
Full support
Mozilla Firefox Supported · Desktop & Mobile
Full support
Apple Safari Supported · macOS & iOS
Full support
Microsoft Edge Supported · Chromium
Full support
Internet Explorer No native support · Use a polyfill
Polyfill
Opera Supported · Modern versions
Full support
Samsung Internet Supported · Android
Full support
Bun Supported · JavaScript runtime
Supported
Deno Supported · JavaScript runtime
Supported
Node.js Supported · Server runtime
Supported
Android WebView Supported · Modern WebView
Full support
_.mixin Lodash 0.1.0+

Bottom line: Safe for production once the full Lodash build is loaded. Prefer _.runInContext() before mixing in shared or library code.

Frequently Asked Questions

_.mixin([object=lodash], source, [options]) copies every own enumerable string-keyed function from source onto object. By default object is Lodash itself, so helpers become _.yourFn() and can join chains when options.chain is true.
When chain is true (default), mixed-in methods stay wrapped in Lodash chains so you can call .value(). When chain is false, a chained call returns the raw result immediately.
Yes. Pass the destination first: _.mixin(myUtils, { greet(name) { return 'Hi ' + name; } }). Returns the same object. Global _ is not changed.
Mixing into the shared _ can clash with other code or overwrite built-ins. _.runInContext() gives a fresh Lodash copy you can extend safely.
No. Only own enumerable function properties on source are added. Nested non-function values are skipped.
No. It is a stable Lodash Util method since 0.1.0. Prefer modules for most apps; use mixin when you want Lodash-style extensions or chaining.

Next: _.noConflict()

Revert _ to its previous owner and keep a Lodash reference.

_.noConflict() tutorial →

About the author

Mari Selvan M P
Mari Selvan M P 🔗

Developer, cloud engineer, and technical writer

  • Experience 12 years building web and cloud systems
  • Focus Full Stack Development, AWS, and Developer Education

I write practical tutorials so students and working developers can learn by doing—from databases and APIs to deployment on AWS.

AWS Certified Developer – Associate (Credly)

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