# oniguruma-to-js

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Convert Oniguruma-flavor Regexp to JavaScript native RegExp.

Supported Oniguruma features:

- `[:alnum:]`, `[:alpha:]` etc. POSIX bracket expressions
- `(?x)` extended, free-spacing mode
- `(?i:..)` flags modifiers
- `(?>..)` atomic group via [`regex`](https://github.com/slevithan/regex)
- `..*+` possessive quantifiers via [`regex`](https://github.com/slevithan/regex)
- `\h` `\H` hex digit shorthands
- `\p{Blank}` `\p{Print}` etc. Oniguruma-flavored unicode property escapes

## Usage

```bash
npm i oniguruma-to-js
```

```ts
import { onigurumaToRegexp } from 'oniguruma-to-js'

const re = onigurumaToRegexp(`[[:alnum:]_]+`)
console.log(re) // /^[a-zA-Z0-9_]+$/
```

```ts
import { construct, syntaxLowering } from 'oniguruma-to-js'

const pattern = syntaxLowering(`(?x:
  \d+    # Match one or more digits
  \s*    # Match zero or more whitespace characters
  [A-Z]+ # Match one or more uppercase letters
)`)
console.log(pattern) // "\d+\s*[A-Z]+"

const re = construct(pattern)
console.log(re) // /\d+\s*[A-Z]+/
```

### Additional Features

#### Lowering TextMate Grammar

Traverse all the regex patterns in a TextMate grammar, and apply `syntaxLowering` to lower the syntax.

```ts
import { loweringTextmateGrammar } from 'oniguruma-to-js/textmate'
import grammar from '../path/to/grammars/json.json'

const lowered = loweringTextmateGrammar(grammar)
```

Note this function will not guarantee the correctness of the result, you may need to verify the result manually.

## Sponsors

<p align="center">
  <a href="https://cdn.jsdelivr.net/gh/antfu/static/sponsors.svg">
    <img src='https://cdn.jsdelivr.net/gh/antfu/static/sponsors.svg'/>
  </a>
</p>

## License

[MIT](./LICENSE) License © 2024-PRESENT [Anthony Fu](https://github.com/antfu)

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