Modern, simple, lightweight (~5kb gzip) form validation library written in Typescript, with no dependencies (no JQuery!). Support a wide range of predefined rules, async, files, dates validation, custom error messages and styles, localization. Supporting writing custom rules and plugins.
NOTE
This is documentation for JustValidate 2. If you are looking for the old version, you could find it here.
It's a right choice for you, if you have a site, a landing page without React, JQuery etc. and you want to quick, simple and powerful solution for validating your form.
- small size and zero dependencies
- no need to change your HTML
- a wide range of pre-defined rules
- custom rules
- support plugins
- custom styles and css classes for invalid fields and error messages
- custom messages
- showing tooltips as error messages
- custom places for the error labels
- localization (defining error messages for different languages)
- user-friendly setup: console warning messages if something incorrect
- written in Typescript and good test coverage
npm install just-validate --saveyarn add just-validateAnd then use it as an imported module:
import JustValidate from 'just-validate';
const validate = new JustValidate('#form');Or if you don't use module bundlers, just include JustValidate script on your page from CDN and call it as window.JustValidate:
<script src="https://unpkg.com/just-validate@latest/dist/just-validate.production.min.js"></script>
<body>
<script>
const validate = new window.JustValidate('#form');
</script>
</body>There are plenty of rules which you could use out of the box:
- required, non-empty fields
- valid email address
- min/max text length
- valid number
- min/max number
- valid password
- valid strong password
- check for the custom regexp
- min/max count of uploaded files
- min/max size, types, extensions, names of uploaded files
- format date, check for isAfter/isBefore dates
Let's say we have a basic HTML layout:
<form action="#" id="form" autocomplete="off">
<label for="name">Enter your name</label>
<input
type="text"
class="form__input form-control"
placeholder="Enter your name"
autocomplete="off"
name="name"
id="name"
/>
<label for="email">Enter your email</label>
<input
type="email"
class="form__input form-control"
placeholder="Enter your email"
autocomplete="off"
name="email"
id="email"
/>
<button class="btn btn-primary" id="submit-btn">Submit</button>
</form>Next, let's add JustValidate to our layout and define some simple rules.
First, we should create the instance new JustValidate('#form') by passing a form selector, or the element as an argument.
Second, we call .addField() with a field selector as the first argument and an array of rules as the second argument.
const validation = new JustValidate('#form');
validation
.addField('#name', [
{
rule: 'minLength',
value: 3,
},
{
rule: 'maxLength',
value: 30,
},
])
.addField('#email', [
{
rule: 'required',
errorMessage: 'Email is required',
},
{
rule: 'email',
errorMessage: 'Email is invalid!',
},
]);And that's it! Now our form is validated!
Please, check out the examples and documentation.
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