# regexpp
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The regular expression parser for ECMAScript.
## 💿 Installation
```bash
$ npm install regexpp
```
- require Node.js 6.5.0 or newer.
## 📖 Usage
```ts
import {
AST,
RegExpParser,
RegExpValidator,
RegExpVisitor,
parseRegExpLiteral,
validateRegExpLiteral,
visitRegExpAST
} from "regexpp"
```
### parseRegExpLiteral(source, options?)
Parse a given regular expression literal then make AST object.
This is equivalent to `new RegExpParser(options).parseLiteral(source)`.
- **Parameters:**
- `source` (`string | RegExp`) The source code to parse.
- `options?` ([`RegExpParser.Options`]) The options to parse.
- **Return:**
- The AST of the regular expression.
### validateRegExpLiteral(source, options?)
Validate a given regular expression literal.
This is equivalent to `new RegExpValidator(options).validateLiteral(source)`.
- **Parameters:**
- `source` (`string`) The source code to validate.
- `options?` ([`RegExpValidator.Options`]) The options to validate.
### visitRegExpAST(ast, handlers)
Visit each node of a given AST.
This is equivalent to `new RegExpVisitor(handlers).visit(ast)`.
- **Parameters:**
- `ast` ([`AST.Node`]) The AST to visit.
- `handlers` ([`RegExpVisitor.Handlers`]) The callbacks.
### RegExpParser
#### new RegExpParser(options?)
- **Parameters:**
- `options?` ([`RegExpParser.Options`]) The options to parse.
#### parser.parseLiteral(source, start?, end?)
Parse a regular expression literal.
- **Parameters:**
- `source` (`string`) The source code to parse. E.g. `"/abc/g"`.
- `start?` (`number`) The start index in the source code. Default is `0`.
- `end?` (`number`) The end index in the source code. Default is `source.length`.
- **Return:**
- The AST of the regular expression.
#### parser.parsePattern(source, start?, end?, uFlag?)
Parse a regular expression pattern.
- **Parameters:**
- `source` (`string`) The source code to parse. E.g. `"abc"`.
- `start?` (`number`) The start index in the source code. Default is `0`.
- `end?` (`number`) The end index in the source code. Default is `source.length`.
- `uFlag?` (`boolean`) The flag to enable Unicode mode.
- **Return:**
- The AST of the regular expression pattern.
#### parser.parseFlags(source, start?, end?)
Parse a regular expression flags.
- **Parameters:**
- `source` (`string`) The source code to parse. E.g. `"gim"`.
- `start?` (`number`) The start index in the source code. Default is `0`.
- `end?` (`number`) The end index in the source code. Default is `source.length`.
- **Return:**
- The AST of the regular expression flags.
### RegExpValidator
#### new RegExpValidator(options)
- **Parameters:**
- `options` ([`RegExpValidator.Options`]) The options to validate.
#### validator.validateLiteral(source, start, end)
Validate a regular expression literal.
- **Parameters:**
- `source` (`string`) The source code to validate.
- `start?` (`number`) The start index in the source code. Default is `0`.
- `end?` (`number`) The end index in the source code. Default is `source.length`.
#### validator.validatePattern(source, start, end, uFlag)
Validate a regular expression pattern.
- **Parameters:**
- `source` (`string`) The source code to validate.
- `start?` (`number`) The start index in the source code. Default is `0`.
- `end?` (`number`) The end index in the source code. Default is `source.length`.
- `uFlag?` (`boolean`) The flag to enable Unicode mode.
#### validator.validateFlags(source, start, end)
Validate a regular expression flags.
- **Parameters:**
- `source` (`string`) The source code to validate.
- `start?` (`number`) The start index in the source code. Default is `0`.
- `end?` (`number`) The end index in the source code. Default is `source.length`.
### RegExpVisitor
#### new RegExpVisitor(handlers)
- **Parameters:**
- `handlers` ([`RegExpVisitor.Handlers`]) The callbacks.
#### visitor.visit(ast)
Validate a regular expression literal.
- **Parameters:**
- `ast` ([`AST.Node`]) The AST to visit.
## 📰 Changelog
- [GitHub Releases](https://github.com/mysticatea/regexpp/releases)
## 🍻 Contributing
Welcome contributing!
Please use GitHub's Issues/PRs.
### Development Tools
- `npm test` runs tests and measures coverage.
- `npm run build` compiles TypeScript source code to `index.js`, `index.js.map`, and `index.d.ts`.
- `npm run clean` removes the temporary files which are created by `npm test` and `npm run build`.
- `npm run lint` runs ESLint.
- `npm run update:test` updates test fixtures.
- `npm run update:ids` updates `src/unicode/ids.ts`.
- `npm run watch` runs tests with `--watch` option.
[`AST.Node`]: src/ast.ts#L4
[`RegExpParser.Options`]: src/parser.ts#L539
[`RegExpValidator.Options`]: src/validator.ts#L127
[`RegExpVisitor.Handlers`]: src/visitor.ts#L204