# Functions ## isUndefined ▸ **isUndefined**(value: *`any`*): `boolean` *Defined in [is/undefined.ts:20](https://github.com/polkadot-js/common/blob/5585a16/packages/util/src/is/undefined.ts#L20)* *__name__*: isUndefined *__signature__*: isUndefined (value: any): boolean *__summary__*: Tests for a `undefined` values. *__description__*: Checks to see if the input value is `undefined`. *__example__*: ```javascript import { isUndefined } from '@polkadot/util'; console.log('isUndefined', isUndefined(void(0))); // => true ``` **Parameters:** | Name | Type | | ------ | ------ | | value | `any` | **Returns:** `boolean` ___