formular

Formular

Easy way to work with forms in React. Using React Hooks 😏

Features

• Just 3kb gzip.
• React hooks included.
• Easy way to start work with forms in React in 2 steps: install and use it 😎.
• Changes made within form rerender only changed fields not everything unlike in most other form libs.

Quick start

Installation

npm install formular

Usage

import { useForm } from 'formular'
import { Input } from 'formular/lib/tags'

const App = () => {
  const form = useForm({
    fields: {
      email: [ required ],
      password: [ required ],
    },
  })

  const handleSubmit = useCallback(() => {
    form.submit()
      .then((values) => {
        // { email: "[e-mail]", password: "strongpass" }
      }, (errors) => {
        // { email: "Required", password: "Required" }
      })
  }, [])  

  return (
    <Fragment>
      <Input field={form.fields.email} />
      <button onClick={handleSubmit}>Submit</button>
    </Fragment>
  )  
}

Or if you need only one field you can just do

import { useField } from 'formular'
import { Input } from 'formular/lib/tags'

const App = () => {
  const field = useField({
    validate: [ required ],
  })
  
  const handleSubmit = useCallback(() => {
    form.validate()
      .then((error) => {
        // { email: "[e-mail]", password: "strongpass" }
      })
  }, [])  


  return (
    <Fragment>
      <Input field={field} />
      <button onClick={handleSubmit}>Submit</button>
    </Fragment>
  ) 
}

Field validation

// validator should return "undefined" if value is valid

const required = (value) => !value && value !== 0 ? 'Required' : undefined 

Examples

• Basics
• Basics
• Async validation

Options

Form

type FormOpts = {
  name?: string
  fields: {
    [key: string]: FieldOpts
  }
  initialValues?: object
}

Field

type FieldOpts = {
  name?: string
  value?: string                // initial value
  validate?: Array<Function>    // list of validators
  readOnly?: boolean
  validationDelay?: number      // adds debounce to validation
}

Interfaces

Form

type FormEntity = {
  name?: string
  opts: FormOpts
  fields: {
    [key: string]: Field
  }
  state: {
    isValid: boolean
    isChanged: boolean
    isValidating: boolean
    isSubmitting: boolean
    isSubmitted: boolean
  }
  setState(values: Partial<State>): void
  setValues(values: object): void
  getValues(): object
  unsetValues(): void
  getErrors(): object
  async validate(): Promise<boolean>
  async submit(): Promise<object>
  on(eventName: string, handler: Function): void
  off(eventName: string, handler: Function): void
}

const form: FormEntity = useForm(opts)

Field

type FieldEntity = {
  form?: Form
  name?: string
  opts: FieldOpts
  node?: HTMLElement
  validators: Array<Function>
  readOnly: boolean
  debounceValidate: Function  // method to call validation with debounce
  state: {
    value: any
    error: any
    isChanged: boolean
    isValidating: boolean
    isValidated: boolean
    isValid: boolean
  }
  setState(values: Partial<State>): void
  setRef(node: HTMLElement): void
  unsetRef(): void
  set(value: any): void
  unset(): void
  validate = (): CancelablePromise
  on(eventName: string, handler: Function): void
  off(eventName: string, handler: Function): void
}

const field: FieldEntity = useField(opts)

Events

Form

form.on('state change', (state) => {
  // triggers on a form's state change
})

form.on('change', (field) => {
  // triggers on a field change
})

form.on('blur', (field) => {
  // triggers on a field blurring
})

Field

form.on('state change', (state) => {
  // triggers on a field's state change
})

field.on('set', (value) => {
  // triggers on a value set
})

field.on('change', (value) => {
  // simlink to "set"
})

field.on('unset', () => {
  // triggers on a value unset
})

field.on('start validate', () => {
  // triggers on a validation start
})

field.on('validate', (error) => {
  // triggers on a validation finish
})

field.on('blur', () => {
  // triggers on a field blurring
})