rommelsantor / react-form-values

React Hook: useFormValues

react-form-values

Custom React hook that simplifies how you can control the state of form fields using a clean and reasonable syntax. Read more at this Medium article.

Install

npm i react-form-values

Prerequisite: npm i react@^16.8.0 react-dom@^16.8.0

API

useFormValues() accepts two parameters:

1. initialValues object - the initial field name/value pairs that serve as the baseline for the form
2. onFormChange function(object) - callback executed with object of name/value pairs whenever any field changes

useFormValues() returns an array with three elements:

1. formValues object - form field name keys mapped to their current values
2. formSetters object - form field name keys mapped to setter function (also appropriate for assignment via onChange)
3. utilities object with the following properties:

• clear function - call this to clear all form fields with a blank value ('')
• isDirty boolean - true if any formValues differ at all from initialValues
• reset function - call this to reset the form to the initialValues

Note: the properties in formSetters can be called by your code arbitrarily with an arbitrary value (it is not required that it only be passed to onChange or an Event object). For example:

formSetters.phoneNumber('949.555.1212') // this will change the value of formValues.phoneNumber

Usage

Basic example

import useFormValues from 'react-form-values'

const MyUserForm = props => {
  const [formValues, formSetters] = useFormValues()

  const onSubmit = event => {
    event.preventDefault()

    console.log('Want to submit form values:', formValues)
  }

  return (
    <form onSubmit={onSubmit}>
      <input
        onChange={formSetters.name}
        value={formValues.name}
      />

      <input
        onChange={formSetters.email}
        value={formValues.email}
      />

      <button type="submit">
        Submit
      </button>
    </form>
  )
}

Pre-populating form, dirty checking, clear, and reset

import useFormValues from 'react-form-values'

const userPreviouslyLoadedViaApi = {
  id: 12345,
  name: 'James Mercer',
  email: '[email protected]',
}

const MyUserForm = props => {
  // third returned element is utilities object
  const [formValues, formSetters, utils] = useFormValues(userPreviouslyLoadedViaApi)

  const onMakeBlank = () => {
    utils.clear()
  }

  const onReset = () => {
    if (utils.isDirty) {
      if (!window.confirm('Your changes to the user will be lost - continue with reset?')) {
        return
      }

      utils.reset()
    }
  }

  return (
    <div>
      <input
        onChange={formSetters.name}
        value={formValues.name}
      />

      <br />

      <input
        onChange={formSetters.email}
        value={formValues.email}
      />

      <br />

      <button
        onClick={onMakeBlank}
        type="button"
      >
        Clear
      </button>

      &nbsp;

      <button
        onClick={onReset}
        type="button"
      >
        Reset
      </button>
    </div>
  )
}