Lodash _.nthArg() Method

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

Definition

Creates a function that returns the argument at index n. Negative n counts from the end (−1 is last). Part of Lodash Util since 3.7.0 (stable — not deprecated).

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

Syntax

Call _.nthArg. Start with this line.

Lodash
_.nthArg([n=0])
CallWhat it does
_.nthArg([n=0])Primary signature.
_.nthArg(...)Call the util helper.

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

Library declarations
Lodash
_.nthArg([n=0])

Parameters

ParameterDescription
nOptional. Index to return (default 0); negative counts from end

Return Value

Return ValueDescription
*A new function that returns args[n]

Lodash Examples

Example 1 — Official: Second Argument

Pick index 1 from ('a', 'b', 'c', 'd').

Lodash
var func = _.nthArg(1);

func('a', 'b', 'c', 'd');
// → 'b'
Try It Yourself

How It Works

  1. Build. _.nthArg(1) returns a picker for index 1.
  2. Call. Pass four arguments: a b c d.
  3. Pick. Slot 1 is 'b'.
  4. Reuse. Call func again with other args anytime.

Example 2 — Official: Negative Index

Count from the end — -2 is second-to-last.

Lodash
var func = _.nthArg(-2);

func('a', 'b', 'c', 'd');
// → 'c'
Try It Yourself

How It Works

  1. Negative. -2 means two steps from the end.
  2. Resolve. Length 4 + (-2) → index 2.
  3. Value. args[2] is 'c'.
  4. Last item. Use _.nthArg(-1) for the final argument.

Example 3 — Default Index 0

Omit n to pick the first argument.

Lodash
var first = _.nthArg();

first('a', 'b', 'c', 'd');
// → 'a'
Try It Yourself

How It Works

  1. Default. Missing n becomes 0.
  2. Same as. _.nthArg(0).
  3. Result. First argument 'a'.
  4. Note. Close to _.identity for a single arg — different when many args arrive.

Example 4 — Out-of-Range Index

A missing slot returns undefined — no error.

Lodash
var func = _.nthArg(5);

func('a', 'b');
// → undefined
Try It Yourself

How It Works

  1. Ask for 5. Only two arguments exist.
  2. Lookup. args[5] is missing.
  3. Return. undefined — never throws.
  4. Guard. Check the result if a missing arg is an error in your app.
Compatibility

Browser & Runtime Support

_.nthArg is a Lodash Util helper since 3.7.0. It runs anywhere Lodash runs — modern browsers (CDN or bundle) and Node.js / Bun / Deno with npm install lodash.

✓ Stable · Lodash 3.7.0+

_.nthArg()

Available in [email protected] full builds and the lodash/nthArg modular import. Works in evergreen browsers and current Node LTS when Lodash is installed.

100% With Lodash 3.7+
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
_.nthArg Lodash 3.7.0+

Bottom line: Safe for production once Lodash is loaded. Prefer import nthArg from "lodash/nthArg" for smaller bundles.

Frequently Asked Questions

_.nthArg(n) returns a new function. When you call that function with any arguments, it returns only the argument at index n — 0 for first, 1 for second, and so on.
Yes. _.nthArg(-1) returns the last argument, _.nthArg(-2) the second-to-last — same idea as counting from the end of an array.
If you omit n, Lodash uses 0. _.nthArg() is the same as _.nthArg(0) and picks the first argument.
You get undefined. _.nthArg(2)('a', 'b') returns undefined because there is no third argument.
When an API wants a unary function but data arrives as multiple arguments — pick the one you need. Useful with _.over, _.flow, or other higher-order helpers.
No. It is a stable Lodash Util method since 3.7.0.

Next: _.over()

Invoke several iteratees with the same arguments and collect results.

_.over() 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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