function atBreak(code) {
    if (code === marker) {
      effects.enter(types.thematicBreakSequence)
      return sequence(code)
    }

    if (
      size >= constants.thematicBreakMarkerCountMin &&
      (code === codes.eof || markdownLineEnding(code))
    ) {
      effects.exit(types.thematicBreak)
      return ok(code)
    }

    return nok(code)
  }
After something, before something else.

```markdown
> | ***
    ^
```

@type {State}