# Step

`import { Step } from "destack:range";`

Protocol for values that can advance through a range.

```ds title="Step"
export newtype interface Step<T = this> {
    next(): T | undefined;
    previous(): T | undefined;
}
```

[language/library/src/range/step.ds:6:12](https://github.com/destack-sh/destack/blob/main/language/library/src/range/step.ds#L6-L12)

## Members

### `next(): T | undefined`

Return the next value.

### `previous(): T | undefined`

Return the previous value.