keysIn

INFO

This function is only available in es-toolkit/compat for compatibility reasons. It either has alternative native JavaScript APIs or isn’t fully optimized yet.

When imported from es-toolkit/compat, it behaves exactly like lodash and provides the same functionalities, as detailed here.

This function retrieves the names of string-keyed properties from an object, including those inherited from its prototype.

• If the value is not an object, it is converted to an object.
• Array-like objects are treated like arrays.
• Sparse arrays with some missing indices are treated like dense arrays.
• If the value is null or undefined, an empty array is returned.
• When handling prototype objects, the constructor property is excluded from the results.

Signature

function keysIn(object?: unknown): string[];

Parameters

• object (unknown): The object to inspect for keys.

Returns

(string[]): An array of string keys from the object.

Examples

const obj = { a: 1, b: 2 };
console.log(keysIn(obj)); // ['a', 'b']

const arr = [1, 2, 3];
console.log(keysIn(arr)); // ['0', '1', '2']

function Foo() {}
Foo.prototype.a = 1;
console.log(keysIn(new Foo())); // ['a']