react-validation

Component to provide simple form validation for React components. It uses the Controlled Components approach for validation.

It is not easy to validate forms with React. The reason is a one-way data flow style. In this case we can't affect forms from the inputs in an easy way. React-validation provides several components which are 'connected' to the form via the input's method attached by the Form component.

DEMO

DEMO src

It is just a validation and doesn't provide any model or something similar. You can use FormData or something like form-serialize to get form data.

NOTE: Always pass the name and validations props. They are required.

Additional markup is allowed inside the Validation.Form markup.

Any additional props (such as event handlers) can also be passed to components.

If you find any bug or error, please feel free to raise an issue. Pull requests are also welcome.

Installation

npm install react-validation

Test

npm run test:dev

Example usage

With @2.*, react-validation is no longer dependent on the external validator. You may use whatever validation strategy you want by extending the rules object. Let's take a look at its initial state:

export default = {};

That's it, just an empty object literal. We don't have any validation rules OOTB because of an extremely high number of possibilities, but it's still recommended to use a well-tested library for known reasons.

So first of all let's extend it and add some rules:

import React from 'react';
// NOTE: Deprecated
import Validation from 'react-validation';
// From v2.10.0
// import { rules, Form, Input, Select, Textarea, Button } from 'react-validation/lib/build/validation.rc'
import validator from 'validator';

// Use Object.assign or any similar API to merge a rules
// NOTE: IE10 doesn't have Object.assign API natively. Use polyfill/babel plugin.
Object.assign(Validation.rules, {
    // Key name maps the rule
    required: {
        // Function to validate value
        // NOTE: value might be a number -> force to string
        rule: value => {
            return value.toString().trim();
        },
        // Function to return hint
        // You may use current value to inject it in some way to the hint
        hint: value => {
            return <span className='form-error is-visible'>Required</span>
        }
    },
    email: {
        // Example usage with external 'validator'
        rule: value => {
            return validator.isEmail(value);
        },
        hint: value => {
            return <span className='form-error is-visible'>{value} isnt an Email.</span>
        }
    },
    // This example shows a way to handle common task - compare two fields for equality
    password: {
        // rule function can accept argument:
        // components - components registered to Form mapped by name
        rule: (value, components) => {
            const password = components.password.state;
            const passwordConfirm = components.passwordConfirm.state;
            const isBothUsed = password
                && passwordConfirm
                && password.isUsed
                && passwordConfirm.isUsed;
            const isBothChanged = isBothUsed && password.isChanged && passwordConfirm.isChanged;

            if (!isBothUsed || !isBothChanged) {
                return true;
            }

            return password.value === passwordConfirm.value;
        },
        hint: () => <span className="form-error is-visible">Passwords should be equal.</span>
    },
    // Define API rule to show hint after API error response
    api: {
        // We don't need the rule here because we will call the 'showError' method by hand on API error
        hint: value => (
            <button
                className="form-error is-visible"
            >
                API Error on "{value}" value. Focus to hide.
            </button>
        )
    }
});

Now we've added required and email to our rules with provided hints. This might be separated in a file where all the rules are registered.

That's it. We can now use it in our React components:

import Validation from 'react-validation';
import React, { Component } from 'react';
import PropTypes from 'prop-types'

export default class Registration extends Component {
    render() {
        return <Validation.components.Form>
            <h3>Registration</h3>
            <div>
                <label>
                    Email*
                    <Validation.components.Input value='[email protected]' name='email' validations={['required', 'email']}/>
                </label>
            </div>
            <div>
                <label>
                    Password*
                    <Validation.components.Input type='password' value='' name='password' validations={['required']}/>
                </label>
            </div>
            <div>
                <Validation.components.Button>Submit</Validation.components.Button>
            </div>
        </Validation.components.Form>;
    }
}

Note the validations prop. It's an array of strings that maps to the rules keys we've extended.

Components and props

react-validation provides a components object that contains Form, Input, Select, Textarea and Button components. All of them are just custom wrappers around the native components. They can accept any valid attributes and a few extra:

1. containerClassName - Input, Select and Textarea: react-validation wraps the native components with an extra block. This prop adds a className to the wrapper.
2. errorContainerClassName: wrapper's error modifier className.
3. validations - Input, Select and Textarea: accepts an array of validations strings that refers to the rules object's keys.
4. errorClassName - Input, Select, Button and Textarea: adds the passed value to className on error occurrences.

NOTE: Always provide a name prop to Input, Select and Textarea. Always pass the validations prop to Input, Select and Textarea.

Form component

Validation.components.Form

The most important component, which provides the heart of react-validation. It basically mixes the binding between the form itself and child react-validation components via context. Any valid props can easily be passed to Form, such onSubmit and method.

Form provides four public methods:

1. validate(name) - validates input with the passed name. The difference between this method and default validation is that validate marks the input as isUsed and isChanged. name - name of the corresponding component.

2. showError(name [,hint]) - helps to handle async API errors. hint - optional hint to show. Can be string (error key, ex 'required') or function which returns hint (jsx).

3. hideError(name) - hides a corresponding component's error.

4. validateAll() - validates all react-validation components. Returns a map (key: field name prop, value: <Array> non passed validation rules) of invalid fields.

export default class Comment extends Component {
    handleSubmit = (event) => {
        event.preventDefault();

        // Emulate async API call
        setTimeout(() => {
            // NOTE: 'api' should be defined on 'extend' step
            this.form.showError('username', 'api');
        }, 1000);
    };

    removeApiError = () => {
        this.form.hideError('username');
    };

    render() {
        return <Validation.components.Form ref={c => { this.form = c }} onSubmit={this.handleSubmit.bind(this)}>
            <div className="row">
                <div className="small-12 columns">
                    <h3>Leave a comment</h3>
                </div>
            </div>
            <div className="row">
                <div className="small-12 medium-4 columns">
                    <label>
                        <Validation.components.Input
                          onFocus={this.removeApiError}
                          placeholder="username"
                          type="text"
                          errorClassName="is-invalid-input"
                          containerClassName=""
                          value="Username"
                          name="username"
                          validations={['required', 'alpha']}
                        />
                    </label>
                </div>
                <div className="small-12 medium-8 columns">
                    <label>
                        <Validation.components.Textarea
                          placeholder="Leave your comment..."
                          errorClassName="is-invalid-input"
                          containerClassName=""
                          value="Comment"
                          name="comment"
                          validations={['required']}
                        />
                    </label>
                </div>
            </div>
            <div className="row">
                <div className="small-12 medium-6 columns">
                    <Validation.components.Button className="button">Submit</Validation.components.Button>
                </div>
            </div>
        </Validation.components.Form>
    }
}

Input component

Validation.components.Input

A wrapper around the native input. It accepts a validations prop - an array of strings that refers to rules object keys.

<Validation.components.Input name='firstname' validations={['alpha', 'lt8']}/>

NOTE: For types radio and checkbox, react-validation will drop the value to an empty string when it's not checked. This is to avoid validation of non-checked inputs.

react-validation will break with the first listed rule, if more than one rule is broken. In the example above (lt8 - value length less than 8), for really long value with d1g1t input value, the alpha rule will break validation first. We can control it by ordering rules within the validations array.

Textarea component

Validation.components.Teaxtarea

A wrapper around the native textarea. Like Input, it accepts a validations prop. Nothing special here:

<Validation.components.Textarea name='comment' value='' validations={['required']}/>

Select component

Validation.components.Select

A wrapper around the native select. Like Input, it accepts a validations prop. Nothing special here:

<Validation.components.Select name='city' value='' validations={['required']}>
    <option value=''>Choose your city</option>
    <option value='1'>London</option>
    <option value='2'>Kyiv</option>
    <option value='3'>New York</option>
</Validation.components.Select>

Button component

Validation.components.Button

A wrapper around the native button. React-validation disables (adds disabled prop) the button on error occurrences. This behavior could be suppressed by passing the disabled prop directly to a component.

Migration from 1.*

extendErrors API

extendErrors no longer exists. Replace it with the new approach of validation rules registration. hint appearance is now fully controlled:

Object.assign(Validation.rules, {
    required: {
        rule: value => {
            return value.trim();
        },
        hint: value => {
            return <span className='form-error is-visible'>Required</span>
        }
    }
});

Defaults

React-validation no longer has any defaults. This is TBD but for a 2.0.0 please provide errorClassName and containerClassName directly to the validation components.

Validations

validations prop now accepts an array of strings instead of objects. It's made to be more simple and reduce render code.

Components API moved to Form API. forceValidate method no longer exist.