React-html5-form

With the package you don't need to re-create form validation logic every time. Instead you take full advantage of HTML5 Constraint Validation API. Besides the package expose no custom input components, instead it provides wrapper InputGroup, which binds inputs (according to configuration) in the children DOM nodes. Thus you can go with both HTML controls and 3rd-party input components.

Highlights

• Input implementation agnostic, can be used any arbitrary input controls (HTML or 3rd-party React components)
• Standard HTML5 syntax for validation constraints (like <input type="email" required maxLength="50" ... />)
• Can be extended with custom validators (again by using standard HTML5 API)
• Can be setup for custom validation messages per input/ValidityState.Property
• Form and input groups expose validity states, so you can use it to toggle scope error messages.
• Form and input groups expose reference to own instances for children DOM nodes. So you can, for example, subscribe for input event and run input group validation (e.g. see On-the-fly validation)
• Can maintain form state both ways: with React Context and Redux

Overview

With Form we define scope of the form. The component exposes parameters valid, error and form. The first reflects actual validity state according to states of registered inputs. The second contains error message (can be set using API). The last one is instance of the component and provides access to the API. With InputGroup we define a fieldset that contains one or more semantically related inputs (e.g. selects day, month, year usually go togather). The group expose valid, error, errors and inputGroup variables on children Nodes. So we can automatically toggle group error message and content classList depending on them. We register inputs within InputGroup with validate prop. There we can specify a validator function, which will extend HTMP5 form validation logic. Very easily we can provide mapping for standard validation message (translate prop).

Installation

npm i react-html5-form

Demo

You can see the component in action at LIVE DEMO :tv:

• source code of example with HTML elements for inputs (styled with Bootstrap 4)
• source code of example with read-made components for inputs (styled with MaterialUI.Next)
• source code of example with connection to Redux

Form

Represents form

import { Form } from "react-html5-form";

Props

• <Function> onSubmit - (OPTIONAL) form submit handler
• <Function> onMount - (OPTIONAL) callback that gets invoked in componentDidMount(), it receives component instance as parameter
• <Function> onUpdate - (OPTIONAL) callback that gets invoked when form ready (all input groups registered) and when it changes validity state. It's intended to be used with Redux to update tree state
• any attributes of Form HTML element

API

• scrollIntoViewFirstInvalidInputGroup() - scroll first input group in invalid state into view (happens automatically onSubmit)
• checkValidityAndUpdateInputGroups() - check form validity and update every input group
• checkValidityAndUpdate() - check form validity and update only form state (without updating input groups)
• setError( message = "") - set form scope error message
• submit() - submit form
• getRef() - get Ref instance pointed to the generated FORM element. Thus if you need to access the DOM node, you go with form.getRef().current
• debugInputGroups( inx = null ) - get debug info about all registered inputs, or one matching given index

Scope parameters

• <String> error - error message set with setError()
• <Boolean> valid - form validity state
• <Boolean> pristine - true if user has not interacted with the form yet.
• <Boolean> submitting - true while form is being processed on submission
• <Boolean> submitted - true after form submitted
• <React.Component> form - link to the component API

State properties valid, pristine, submitting, submitted are also available as element data-attributes e.g. data-submitting="false"

Defining component

import React from "react";
import { render } from "react-dom";
import { Form } from "react-html5-form";

const MyForm = props => (
  <Form id="myform">
  {({ error, valid }) => (
      <>
      Form content
      </>
    )}
  </Form>
);

render( <MyForm />, document.getElementById( "app" ) );

<Form> creates <form noValidate ..> wrapper for passed in children. It delegates properties to the produced HTML Element. For example specified id ends up in the generated form.

Accessing Form API

async function onSubmit( form ) {
  form.setError("Opps, a server error");
  return Promise.resolve();
};

const MyForm = props => (
  <Form onSubmit={onSubmit} id="myform">
  {({ error, valid, pristine, submitting, form }) => (
      <>
      { error && (<div className="alert alert-danger" role="alert">
            <strong>Oh snap!</strong> {error}
          </div>)
      }
      Form content

      <button disabled={ ( pristine || submitting ) } type="submit">Submit</button>

      </>
    )}
  </Form>
);

The API can be accessed by form reference. Besides, any handler passed through onSubmit prop gets wrapped. The component calls setState for checkValidity prior calling the specified handler. From the handler you can access the API by reference like form.setError. What is more, we disable submit button until the user first interaction with the form and on form submission (onSubmit is an asynchronous function / Promise; as it resolves the state property submitting` set in false).

InputGroup

InputGroup defines scope and API for a group of arbitrary inputs registered with validate prop. InputGroup exposes in the scope parameters that can be used to toggle group validation message(s), group state representation and to access the component API

import { Form, InputGroup } from "react-html5-form";

Props

• <Object|Array> validate - (REQUIRED) register inputs to the group. Accepts either array of input names (to match [name=*]) or plain object out of pairs name: custom validator

// Group of a single input
<InputGroup validate={[ "email" ]} />
// Group of multiple inputs
<InputGroup validate={[ "month", "year" ]} />
// Custom validator
<InputGroup validate={{
          "vatId": ( input ) => {
            if ( !input.current.value.startsWith( "DE" ) ) {
              input.setCustomValidity( "Code must start with DE" );
              return false;
            }
            return true;
          }
        }}>