The ultimate JavaScript validation library you've ever needed.
Dead simple fluent API. Customizable. Reusable.

npm version npm bundle size (minified + gzip)

Installation - Documentation - API

## Introducing v8n > **v8n** is an acronym for **v**_alidatio_**n**. Notice that it has exactly > eight letters between **v** and **n** in the _"validation"_ word. This is the > same pattern we are used to seeing with _i18n_, _a11y_, _l10n_ ... ### Chainable API Create validations very easily with its chainable API: ```javascript v8n() .string() .minLength(5) .first("H") .last("o") .test("Hello"); // true ``` ### Incredibly fluent Mix **rules** and **modifiers** together to create complex validations with great ease and fluency: ```javascript v8n() .array() .every.number() .not.some.negative() .test([1, 2, -3]); // false - no negative please! ``` So fluent that it looks like English: ```javascript v8n() .some.not.uppercase() // expects that some character is not uppercase .test("Hello"); // true v8n() .not.some.uppercase() // expects that no character is uppercase .test("Hello"); // false ``` Notice how we made very different validation strategies just by changing the order of the modifiers. It's so intuitive that seems to be impossible, but this is v8n. ### Customizable Create your own **custom validation rules** in a very intuitive way: ```javascript function foo() { return value => value === "bar"; } v8n.extend({ foo }); ``` v8n will treat them like built-in ones: ```javascript v8n() .string() .foo() .test("bar"); // true ``` ### Reusable Export validations just like you're used to do with your JavaScript modules: _specialNumber.js_ ```javascript import v8n from "v8n"; export default v8n() .number() .between(50, 100) .not.even(); ``` and use them anywhere you want: ```javascript import specialNumber from "../specialNumber"; specialNumber.test(63); // true ``` ### For any kind of data Use v8n to validate your data regardless of its type. You can validate primitives, arrays, objects and whatever you want! You can also use them together! ```javascript // numbers v8n() .number() .between(5, 10) .test(7); //true // strings v8n() .string() .minLength(3) .test("foo"); // true // arrays v8n() .array() .every.even() .test([2, 4, 6]); // true // objects const myData = { id: "fe03" }; v8n() .schema({ id: v8n().string() }) .test(myData); // true ``` ### For any kind of validation Do simple validations with boolean based tests. Get more information about your validation process with exception based tests. And of course, perform asynchronous tests as well. All in one library. #### Boolean based validation: ```javascript v8n() .string() .first("H") .test("Hello"); // true ``` #### Exception based validation: ```javascript try { v8n() .string() .first("b") .check("foo"); } catch (ex) { console.log(ex.rule.name); // first } ``` #### Getting all failures: ```javascript const failed = v8n() .string() .minLength(3) .testAll(10); failed; // [ // ValidationError { rule: { name: "string", ... } }, // ValidationError { rule: { name: "minLength", ... } } // ] ``` #### Async validation: If your validation strategy has some rule that performs time consuming validation, like a back-end check, you should use asynchronous validation: ```javascript v8n() .somAsyncRule() .testAsync("foo") // returns a Promise .then(result => { /* valid! */ }) .catch(ex => { /* invalid! */ }); ``` ### Shareable Share your rules with the world, and use theirs as well. Create useful validation rules and share them with the open source community, and let people around the world validate without reinventing the wheel. ### Ready to use! There are a lot of built-in rules and modifiers for you to use already implemented in `v8n`'s core. Take a look at all of them in our [API](https://imbrn.github.io/v8n/api/) page. But if you can't find what you need, go ahead and make it. ### Tiny! All these incredible features for just a few bytes: ![npm bundle size (minified + gzip)](https://img.shields.io/bundlephobia/minzip/v8n.svg) ## Architecture The **v8n** core is composed of `rules` and `modifiers`. They are used together to build complex validations in an easy way. ### Rules Rules are the heart of the `v8n` ecosystem. You use them to build your validation strategies: ```javascript v8n() .string() .minLength(3) .test("Hello"); // true ``` In this code snippet, we're using two rules (`string` and `minLength`) to build our validation strategy. So our validated value (`"Hello"`) is valid because it's a string and it is at least 3 characters long. > Rules can be more powerful if used along with _modifiers_. Learn about them in > the next section. ### Modifiers Modifiers can be used to change rules meaning. For example, you can use the `not` modifier to expect the reversed result from a rule: ```javascript v8n() .not.equal(5) .test(5); // false ``` > You can check all available modifiers on our documentation page. Modifiers are very powerful. They work as decorators for rules. When used together, they allow you to build very complex validations. ## Contribute Contributions of any kind are welcome! Read our [CONTRIBUTING](./.github/CONTRIBUTING.md) guide. ## License [MIT License](https://opensource.org/licenses/MIT)

	Stars	Issues	Version	Updated	Created
ajv	13,391	322	8.12.0	a year ago	9 years ago
joi	20,617	162	17.13.0	6 days ago	12 years ago
runtypes	2,547	71	6.7.0	a year ago	8 years ago
v8n			1.5.1	2 years ago	6 years ago
validate.js	2,627	119	0.13.1	5 years ago	10 years ago
yup	22,229	218	1.4.0	2 months ago	10 years ago

ajv vs joi vs runtypes vs v8n vs validate.js vs yup

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