# js-validation
Lightweight, zero-dependency vanilla JavaScript form validation library inspired by [`jquery-validation`](https://github.com/jquery-validation/jquery-validation/).
## Features
- No dependency (pure JS)
- Modular rules – each rule lives in its own file under `src/rules/`
- Built-in rules: `required`, `email`, `minlength`, `maxlength`, `pattern`, `equalTo`, `notEqualTo`, `numeric`, `url`, `date`, `dateISO`, `maxfiles`, `maxsize`, [`etc`](https://js-validation.js.org/rules/)
- Extensible with custom rules via `addMethod`
- Build with **Vite** – outputs `js-validation.js` and `js-validation.min.js`
- Test with **Vitest**
## Installation
### NPM
```bash
npm install @phpdevsr/js-validation
```
### CDN (jsDelivr)
```html
```
## Build
```bash
npm run build
```
Produces in `dist/`:
- `js-validation.js` – UMD (unminified)
- `js-validation.min.js` – UMD (minified)
- `js-validation.esm.js` – ES module (unminified)
- `js-validation.esm.min.js` – ES module (minified)
## Test
```bash
npm test
```
## Usage (ES module)
### Default import (all rules included)
```js
import jsValidation from '@phpdevsr/js-validation';
const validator = jsValidation('#signup', {
rules: {
email: { required: true, email: true },
password: { required: true, minlength: 6 },
confirmPassword: { required: true, equalTo: '#password' }
},
messages: {
confirmPassword: { equalTo: 'Passwords must match.' }
}
}).submit((form) => {
// Only fires when all fields are valid
fetch('/api/signup', { method: 'POST', body: new FormData(form) });
});
```
### Selective import (choose only the rules you need)
```js
// Import core without any rules
import jsValidation from '@phpdevsr/js-validation/core';
// Then import only the specific rules you need
import '@phpdevsr/js-validation/rules/required';
import '@phpdevsr/js-validation/rules/email';
// Available rules: required, email, minlength, maxlength, pattern, equalTo, notEqualTo, numeric, url, date, dateISO, maxfiles, maxsize
const validator = jsValidation('#contact', {
rules: {
name: { required: true },
email: { required: true, email: true }
}
}).submit((form) => {
fetch('/api/contact', { method: 'POST', body: new FormData(form) });
});
```
## Usage (UMD / browser script tag)
```html
```
## Custom rule
```js
import jsValidation from 'js-validation';
jsValidation.addMethod('startsWithA', (value) => value.startsWith('A'), 'Must start with letter A.');
```
## Contributing
We **are** accepting contributions from the community! It doesn't matter whether you can code, write documentation, or help find bugs,
all contributions are welcome.
Please read the [*CONTRIBUTING.md*](https://github.com/PHPDevsr/js-validation/blob/develop/CONTRIBUTING.md).
This project has had thousands on contributions from people since its creation. This project would not be what it is without them.
Made with [contrib.rocks](https://contrib.rocks).
