regexpstructor
Version:
Build regular expressions in a safe and readable way.
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Markdown
[](https://github.com/mister-what/regexpstructor/actions/workflows/test.yml)
[](https://www.npmjs.com/package/regexpstructor)
> Build regular expressions via a fluent api
- Describe your matcher in a human readable way
- Fluent api to build your regular expressions
- Make maintainable complex regular expressions
- **Immutable for maximum reuseablity:** All methods return a fresh RegExpstructor. No implicit mutation of any internals that could lead to unexpected results
- **Composable:** Build more complex expressions from your simple RegExpstructors. Use combinators like `ReStructor.seq(...RegExpstructors)` or `ReStructor.or(...RegExpstructors)` to combine your matchers.
- No useless non-capture group wrapping in the output (the final Regexp will be as performant and readable as possible)
## Getting started
Install with
```sh
npm i regexpstructor
```
or with yarn
```sh
yarn add regexpstructor
```
## Usage
```js
// ES module import:
import ReStructor from "regexpstructor";
// or in commonjs:
const ReStructor = require("regexpstructor");
/**
* @example building a UUID regexp
*/
const hexChar = ReStructor().charOfRanges(["0", "9"], ["a", "f"]);
// tests for [0-9a-f]{8} - eg. "a019bc3f"
const digitBlock_8 = hexChar.repeatExactly(8);
// tests for [0-9a-f]{4} - eg. "bc3f"
const digitBlock_4 = hexChar.repeatExactly(4);
// uuid looks like this: "a019bc3f-1234-5678-9abc-def012345678"
const uuid = digitBlock_8
.then("-")
.then(
// 3 times a 4-digit blocks, each followed by a dash
digitBlock_4.then("-").repeatExactly(3)
)
.then(
// block of size 12
hexChar.repeatExactly(12)
)
.withAnyCase() // make case insensitive
.searchOneLine(); // single line search
// compile the uuid reStructor into a regExp
const regex = uuid.compile();
// use it:
regex.test("a019bc3f-1234-5678-9abc-def012345678"); // result: true
// print it:
console.log(regex); /* logs: /[0-9a-f]{8}-(?:[0-9a-f]{4}-){3}[0-9a-f]{12}/gi */
```