# isFtKeyStore · FT4 TypeScript client · Chromia Docs (concept)

> isFtKeyStore(keyStore: Signer ): keyStore is FtKeyStore Type assertion function that checks if the specified signer is an FtKeystore Parameters keyStore: S

Source: https://docs.chromia.com/pages/ft4-ts-client/functions/authentication.isFtKeyStore/

Function

# isFtKeyStore

* ```signature
  isFtKeyStore(keyStore: Signer): keyStore is FtKeyStore
  ```

  Type assertion function that checks if the specified signer is an `FtKeystore`

  #### Parameters

  + keyStore: [Signer](https://docs.chromia.com/pages/ft4-ts-client/types/authentication.Signer/)

    the signer to check

  #### Returns keyStore is [FtKeyStore](https://docs.chromia.com/pages/ft4-ts-client/interfaces/authentication.FtKeyStore/)

  true if the specified signer was an `FtKeystore`. Else, false.

[View this page on docs.chromia.com](https://docs.chromia.com/pages/ft4-ts-client/functions/authentication.isFtKeyStore.html)Generated API reference, mirrored from the live docs