# contains

`import { contains } from "destack:bytes";`

Return whether `bytes` contains `needle`.

```ds title="contains"
export function contains(bytes: &'a readonly [uint8], needle: &'b readonly [uint8]): boolean
```

[language/library/src/bytes/bytes.ds:173:175](https://github.com/destack-sh/destack/blob/main/language/library/src/bytes/bytes.ds#L173-L175)