Extract Object Keys

extractObjectKeys

Extracts the keys of an object with proper typing.

Import

import { extractObjectKeys } from 'nhb-toolbox';

Usage

Basic Usage

const obj = { a: 1, b: 2, c: 3 };
const keys = extractObjectKeys(obj); // Returns ['a', 'b', 'c']

With Empty Object

TypeScript will complain and it will return empty array.

const keys = extractObjectKeys({}); // Returns []

With Null/Undefined

TypeScript will complain and it will return empty array.

const keys = extractObjectKeys(null); // Returns []
const keys = extractObjectKeys(undefined); // Returns []

API

Type Parameters

Parameter	Description
T	A generic object type

Parameters

Parameter	Type	Description
obj	T	The object to extract keys from

Return Value

Array<keyof T>: An array of keys from the specified object, or empty array if the object is null/undefined/empty.

Examples

Simple Object

const user = {
  id: 1,
  name: 'John Doe',
  email: 'john@example.com'
};

const keys = extractObjectKeys(user); // ['id', 'name', 'email']

Nested Object

const product = {
  id: 1,
  name: 'Laptop',
  details: {
    brand: 'Dell',
    price: 999
  }
};

const keys = extractObjectKeys(product); // ['id', 'name', 'details']
// Note: Only top-level keys are returned

Edge Cases

TypeScript will complain and it will return empty array.

// Empty object
extractObjectKeys({}); // []

// Null case
extractObjectKeys(null); // []

// Undefined case
extractObjectKeys(undefined); // []

// Non-object values
extractObjectKeys('string'); // []
extractObjectKeys(123); // []

Notes

• This function only returns top-level (own) enumerable properties
• Returns an empty array for empty objects, null, undefined, or non-object values
• Internally uses Object.keys() with proper TypeScript typing
• Symbol-keyed properties are not included in the result
• Inherited properties are not included (only own properties)
• The return type is properly typed as Array<keyof T> for better TypeScript support
• For nested objects, only the top-level keys are extracted