isError()function

isError(v: unknown): v is Error & { readonly code?: string | undefined }

Param	Type
`v`	`unknown`	The value to check and narrow. required

Return
`v is Error & { readonly code?: string \| undefined }`	`true` if `v` is an `Error` (narrowing it, with an optional `code` string).

Is an unknown value an Error instance?

Uses the native Error.isError() if available, otherwise falls back to instanceof Error.