decamelize-keys

September 20, 2026 · View on GitHub

Convert object keys from camel case using decamelize

Install

npm install decamelize-keys

Usage

import decamelizeKeys from 'decamelize-keys';

// Convert an object
decamelizeKeys({fooBar: true});
//=> {foo_bar: true}

// Convert an array of objects
decamelizeKeys([{fooBar: true}, {barFoo: false}]);
//=> [{foo_bar: true}, {bar_foo: false}]

API

decamelizeKeys(input, options?)

input

Type: object | object[]

An object or array of objects to decamelize.

options

Type: object

separator

Type: string
Default: '_'

The character or string used to separate words.

import decamelizeKeys from 'decamelize-keys';

decamelizeKeys({fooBar: true});
//=> {foo_bar: true}

decamelizeKeys({fooBar: true}, {separator: '-'});
//=> {'foo-bar': true}
exclude

Type: Array<string | RegExp>
Default: []

Exclude keys from being decamelized.

deep

Type: boolean
Default: false

Recurse nested objects and objects in arrays.

import decamelizeKeys from 'decamelize-keys';

decamelizeKeys({fooBar: true, nested: {unicornRainbow: true}}, {deep: true});
//=> {foo_bar: true, nested: {unicorn_rainbow: true}}
stopPaths

Type: string[]
Default: []

Exclude children at the given object paths in dot-notation from being decamelized. This option only has an effect together with the deep option.

The paths use the input key casing, so for example, with an object like {aB: {cD: '🦄'}}, the object path to reach the unicorn is 'aB.cD'.

The key at a stopped path is still decamelized. Only its children are left alone.

For correct TypeScript types when using this option, add as const to the array.

import decamelizeKeys from 'decamelize-keys';

const object = {
	aB: 1,
	aC: {
		cD: 1,
		cE: {
			eF: 1
		}
	}
};

decamelizeKeys(object, {
	deep: true,
	stopPaths: [
		'aC.cE'
	]
});
/*
{
	a_b: 1,
	a_c: {
		c_d: 1,
		c_e: {
			eF: 1
		}
	}
}
*/

When an object is inside an array, the path is specified without array indices. A stopPath applies to all items in the array.

import decamelizeKeys from 'decamelize-keys';

const object = {
	fooBar: [
		{
			barBaz: {
				quxQuux: 'value'
			}
		}
	]
};

decamelizeKeys(object, {
	deep: true,
	stopPaths: [
		'fooBar.barBaz'
	]
});
/*
{
	foo_bar: [
		{
			bar_baz: {
				quxQuux: 'value'
			}
		}
	]
}
*/