# Functions ## isObservable ▸ **isObservable**(value: *`any`*): `boolean` *Defined in [is/observable.ts:27](https://github.com/polkadot-js/common/blob/1fb1f9d/packages/util/src/is/observable.ts#L27)* *__name__*: isBObservable *__signature__*: isObservable (value: any): boolean *__summary__*: Tests for a `Observable` object instance. *__description__*: Checks to see if the input object is an instance of `BN` (bn.js). *__example__*: ```javascript import { isObservable } from '@polkadot/util'; console.log('isObservable', isObservable(...)); ``` **Parameters:** | Param | Type | | ------ | ------ | | value | `any` | **Returns:** `boolean` ___