README.md

React Form Validation using ValidityState object

This project was bootstrapped with Create React App.

Available Scripts

In the project directory, you can run:

yarn start

Runs the app in the development mode.
Open http://localhost:3000 to view it in the browser.

The page will reload if you make edits.
You will also see any lint errors in the console.

yarn test

Launches the test runner in the interactive watch mode.
See the section about running tests for more information.

yarn build

Builds the app for production to the build folder.
It correctly bundles React in production mode and optimizes the build for the best performance.

The build is minified and the filenames include the hashes.
Your app is ready to be deployed!

See the section about deployment for more information.

Usage

Declare validation constraints using builtin input tag attributes like:

• required
• pattern
• min
• max

Violations of the declared attributes will be reflected in the ValidityState object

import { Input } from "./components/input";

<Input
    id="name"
    name="name"
    inputLabel="Name*"
    required
    maxLength="45"
    errorLabel="Name is required"
/>

For multiple error messages use errorLabels instead of single errorLabel. errorLabels keys must match the ValidityState object ones.

import { Input } from "./components/input";

<Input
    type="number"
    id="age"
    name="age"
    inputLabel="Age [18-100]*"
    required
    min="18"
    max="100"
    errorLabels={{
        valueMissing: "Age is required",
        rangeUnderflow: "Please enter a number > 18",
        rangeOverflow: "Please enter a number < 100",
    }}
/>

To trigger validation on external conditions (e.g. on form submit), set propagatedTouch prop to true

import React, { useRef, useState } from 'react';
import { Input } from "./components/input";

export const FormComponent = () => {
    const [formTouched, setFormTouched] = useState(false);
    const formElement = useRef(null);
    
    const handleSubmit = (event) => {
          setFormTouched(true);
          event.preventDefault();
          
          if (formElement.current.reportValidity()) {
            alert('all good!');
          }
      };
    
    <form onSubmit={handleSubmit}
          ref={formElement}
          noValidate={true}>
        <Input
            type="email"
            id="email"
            name="email"
            inputLabel="Email*"
            required
            errorLabel="You must enter a valid email address"
            propagatedTouch={formTouched}
        />
        <button type="submit">
            Submit
        </button>
    </form>
}