Lodash _.isFinite() Method

Beginner
5 min read
Updated: Nov 2026
5 examples
Lang
Decorative image with the word ISFINITE

Definition

Checks if value is a finite primitive number. Based on Number.isFinite — no type coercion. Since Lodash 0.1.0.

Pass the value you want to inspect or convert. Read the return type carefully before you use the result.

Syntax

Call _.isFinite. Start with this line.

Lodash
_.isFinite(value)
CallWhat it does
_.isFinite(value)Primary signature.

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

Library declarations
Lodash
_.isFinite(value)

Parameters

ParameterDescription
valueRequired. The value to check

Return Value

Return ValueDescription
*true if finite primitive number

Lodash Examples

Example 1 — Official: Basics

Finite numbers pass; Infinity and numeric strings fail.

Lodash
_.isFinite(3);
// → true

_.isFinite(Number.MIN_VALUE);
// → true

_.isFinite(Infinity);
// → false

_.isFinite("3");
// → false
Try It Yourself

How It Works

  1. 3 is a finite primitive → true.
  2. MIN_VALUE is a tiny finite float → true.
  3. Infinity is a number but not finite → false.
  4. "3" is a string — no coercion → false.

Example 2 — vs Global isFinite

Global isFinite coerces; Lodash does not.

Lodash
isFinite("3");
// → true   (coerces string → 3)

_.isFinite("3");
// → false

Number.isFinite("3");
// → false  (same idea as Lodash)
Try It Yourself

How It Works

  1. Global isFinite converts "3" to a number first.
  2. Lodash / Number.isFinite require typeof === "number".
  3. Result. Same string, different answers.
  4. Rule. Parse form strings yourself, then call _.isFinite.

Example 3 — NaN and -Infinity

Special IEEE values are numbers, but not finite.

Lodash
_.isFinite(NaN);
// → false

_.isFinite(-Infinity);
// → false

_.isNumber(NaN);
// → true   // still a number type

_.isFinite(-0);
// → true
Try It Yourself

How It Works

  1. NaN / -Infinity fail the finite test.
  2. isNumber(NaN) can still be true — different helper.
  3. -0 is a finite number → true.
  4. Use isFinite when math must stay in range.

Example 4 — Boxed Numbers and Booleans

Objects and booleans are not primitive numbers.

Lodash
_.isFinite(new Number(5));
// → false

_.isFinite(true);
// → false

isFinite(true);
// → true   // global coerces true → 1
Try It Yourself

How It Works

  1. new Number(5) is an object → Lodash false.
  2. true is a boolean → Lodash false.
  3. Global isFinite(true) coerces to 1 → true.
  4. Lesson. Strict checks avoid surprise coercions.

Example 5 — Safe Input Guard

Parse a string, then confirm the result is finite.

Lodash
function safeNumber(input) {
  var n = Number(input);
  return _.isFinite(n) ? n : null;
}

safeNumber("42");
// → 42

safeNumber("oops");
// → null

safeNumber("Infinity");
// → null
Try It Yourself

How It Works

  1. Number(input) converts the string deliberately.
  2. isFinite rejects NaN and Infinity.
  3. "42" → finite → return 42.
  4. Bad / Infinite inputs → null fallback.
Compatibility

Browser & Runtime Support

_.isFinite is a Lodash Lang helper (since 0.1.0). It runs anywhere Lodash 4.x runs — modern browsers (CDN or bundle) and Node.js / Bun / Deno with npm install lodash. Behavior aligns with Number.isFinite.

✓ Stable · Lodash 0.1.0+

_.isFinite()

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

100% With Lodash 4.x
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
_.isFinite Lodash 0.1.0+

Bottom line: Safe for production once Lodash is loaded. Prefer import isFinite from "lodash/isFinite". Native Number.isFinite is a fine alternative when Lodash is not needed.

Frequently Asked Questions

_.isFinite(value) returns true if value is a finite primitive number — not Infinity, -Infinity, or NaN, and not a coerced string.
Global isFinite coerces values (isFinite("3") is true). Lodash does not coerce — _.isFinite("3") is false. It follows Number.isFinite.
Yes for everyday inputs. Lodash documents that this method is based on Number.isFinite.
No. Boxed numbers have typeof "object". Lodash expects a primitive number.
Yes. Negative zero is still a finite number, so _.isFinite(-0) is true.
Use import isFinite from "lodash/isFinite" or require("lodash/isFinite") for tree-shaking. Full build: import _ from "lodash" then _.isFinite.

Next: _.isFunction()

Check whether a value is a function.

_.isFunction() 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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