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# init(_:_:)

Creates a regex component that matches the given component
zero or one times.

```
init(_ component: some RegexComponent, _ behavior: RegexRepetitionBehavior? = nil) where Output == Substring
```

## Parameters

`component`

The regex component.

`behavior`

The repetition behavior to use when repeating
`component` in the match. If `behavior` is `nil`, the default
repetition behavior is used, which can be changed from
`eager` by calling `repetitionBehavior(_:)` on the resulting
`Regex`.

---

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