This library allows your React application to automatically generate forms using ReactHookForm. The form and validations are generated following a schema inspired by SimpleSchema.

Contents

• Usage
  • 1. Write schema
  • 2. Render a form
  • 3. Make it prettier
  • 4. Translate labels
• Available skins
• Roadmap
• Documentation
  • Types
    • Select and radios
  • Validators
    • validate validator
  • Other schema fields
  • Schema
  • Autoform component
  • Config
  • Field props override
  • Coercers
  • Translation
    • tr()
    • stringExists()
    • Variable substitution
    • Adding strings
    • Multilanguage
    • Translation utils
    • Use your own
  • Extending
    • Skinning tutorial
  • Overriding
    • Skin component
    • Rendering
• Extending
• Extending tutorial
• Importing base

Play with the demos

• Emergency styles
• Bootstrap 4
• Material-UI
• Blueprint

Full webpack project demos

• Play with the bootstrap4 demo. Project.
• Play with emergency styles demo. Project.
• Play with Material-UI demo. Project
• (new!) React Native

Installation

$ npm install react-hook-form react-hook-form-auto --save

Deprecated

• 1.2.0 works with react-hook-form 6+.
• 1.1.0 works with react-hook-form 4+. Older versions of this library (1.0.x) will only work with version 3 of react-hook-form.

Usage

1. Write schema

Write a schema for each model you have:

    import { createSchema } from 'react-hook-form-auto'
 
    export const client = createSchema('client', {
      name: {
        type: 'string',
        required: true,
        max: 32
      },
      age: {
        type: 'number'
      }
    })

In this example we are stating that a client is required to have a name and providing its allowed length. Also client has age and it's a number.

2. Render a form

<Autoform /> React component will generate inputs including translatable label, proper input types and error messages.

    import { Autoform } from 'react-hook-form-auto'
    import { client } from './models/client'
 
    const MyForm = ({ onSubmit }) =>
      <Autoform
        schema={client}
        onSubmit={onSubmit}
      />

Form will be validated following the rules set by the schema.

It also allows you to build arrays from other schemas. Simply specify the other schema within brackets [<other>]. Autoform default skin will allow you to add and remove elements.

    import { createSchema } from 'react-hook-form-auto'
    import { client } from './client'
 
    export const company = createSchema('company', {
      clients: {
        type: [client],
        minChildren: 10
      }
    })

3. Make it prettier

3a. Make it less ugly with some styling

Install the emergency styles if you don't want to bundle a whole bootstrap.

$ npm install rhfa-emergency-styles --save

Then set the styles prop of <Autoform />:

    import styles from 'rhfa-emergency-styles'
 
    // With sass...
    import 'rhfa-emergency-styles/prefixed.sass'
    // ...or without
    import 'rhfa-emergency-styles/dist/styles.css'
 
    <Autoform styles={styles} />

If you use sass you have to make sure you are not excluding node_modules in your build process.

If you use css-modules you have better options.

3b. Make it pretty with Bootstrap 4

We can take advantage of the styling strategy and pass bootstrap classes as styles props. You can grab them from here [raw]. Then use them:

    import styles from './bsStyles'  // copy-pasted styles description
 
    <Autoform styles={styles} />

As you have to pass the styles on every Autoform render, I recommend creating a module or a HoC.

Read the documentation to find out what else you can do.

4. Translate

You probably see labels like models.client.name instead of the proper ones. That's because the project uses a built-in translation system. You can setup those strings both at once or incrementally.

Simple call addTranslations directly in your module or modules. Example:

    import { addTranslations } from 'react-hook-form-auto'
 
    addTranslations({
      models: {
        client: {
          name: 'Name',
          age: 'Age'
        }
      }
    })

A simple way to fill this is by replicating the unstranslated string in the object. The dot is a subobject. In the former example you would see a label called models.client.name.

Available skins

Some of them need other imports. See instructions from each.

Vanilla (here)

Bootstrap 4 (as instructed in this document)

Material-UI

Blueprint

React Native

Rationale

One of the purposes of the library is to avoid repeating code by not having to write a set of input components for every entity. Also when time is of the essence, writing forms can be exasperating.

These are some of the advantages of using an automatic form system.

• More DRY
• More SSoT
• ...so less bugs

Also react-hook-form-auto has some of its own

• Includes a translation system
• It's easily expandable
• It's simple
• When possible tries to use convention over configuration

Roadmap

Actually there aren't clearly defined goals. The library already suits my personal needs. Do you need anything that is not there? Feel free to write an issue! Those are the tasks I think may be interesting and will randomly work on them:

• Automatic form generation
• Able to stylize components
• Datatype coertion
• Provide more and better styling examples
• Styles to make it look like bootstrap4
• Native components for famous ui libraries like bootstrap4
  • Need other? Open issue!
• Translated messages from server/async
• Actually limit children
• React Native support
• Typescript

Documentation

Types

Each schema can be regarded as a Rails model or a database table. You can store them anywhere, for example in a module:

    import { createSchema } from 'react-hook-form-auto'
 
    export const computer = createSchema('computers', { /* ...schema... */ })

Each first level entry in the schema object represents the fields in the form or the columns in the database analogy. To configure the field you use another object. Example:

    {
      name: { type: 'string' }
    }

These are the types a field can be:

You can specify the type as a constructor. There's not an easily measurable advantage. Example:

    { type: String }

select and radios

They both allow options as an array that can be one of strings with the options keys that will be feed to translator using trModel() or can be objects in the form { value, label }. If an object is provided, label will be used for the HTML content (display) and value for the option's value.

Options can also be a function. In that case it will be evaluated with the component props as the first argument. The results used as explained above, that is, array of strings or objects.

Example with keys:

    {
      type: 'select',
      options: ['red', 'blue']
    }

Example with objects:

    {
      type: 'select',
      options: [
        { value: 'r', label: 'red' },
        { value: 'b', label: 'blue' }
      ]
    }

Example with function. This example assumes Autoform component has a color collection in the props:

    {
      type: 'select',
      options: props => props.colors.map(color => ({
        value: color.id,
        label: color.name
      }))
    }

Validators

The string returned will be translated. The translation will receive the field's schema as variables.

The validate validator

The function used to validate the field, as any other validator, can return

• true to fail (and automatically generate message) or false to pass
• An string that will be the error message

Other schema fields

There are some other attributes you can pass while defining the field schema:

Schema

The schema establishes the validation and inputs. The instance can be stored anywhere, like your own model object or a module. At the moment it doesn't change over time.

createSchema

Creates a Schema from the specification.

Kind: global function

Autoform component

The <Autoform /> component accepts the following props

Any other prop will be passed to the skin render().

Config

The config prop is an object that has the following attributes

Field props override

You can override field props individually. You can do this with a component called FieldPropsOverride. This is useful when you want to create an special field with some functionality that forces you to provide an event handler. Let's see an example:

    import { Autoform, FieldPropsOverride } from 'react-hook-form-auto'
 
    const Component = ({ onKeyDown }) =>
      <Autoform schema={client}>
        <FieldPropsOverride
          name="name"
          onKeyDown={onKeyDown}
        />
      </Autoform>

The name should specify the path without taking into account array order. For example, if a pet serves as an schema array for an owner and you want to override every pet name from pets field (array), you should use pets.name as the name prop:

    <FieldPropsOverride
      name="pets.name"
      ...overrides...
    />

Coercers

While react-hook-form works with inputs, this library is focused in models. This means:

• Values from inputs are coerced to the datatype you define in the schema.
• Default values are left untouched if there they are not defined or registered.
• You can manually use setValue from your skin or skinOverride.

You can also disable coercers with the Autoform's disableCoercing prop.

Select

Select will include an empty option for uninitialized elements. Please, write an issue if you want this to be configurable.

Imperative handling

Autoform component sets some functions to be used in referenced component:

    let formRef
 
    // Example: imperative submit
    const doSubmit = () => {
      formRef.submit()
    }
 
    const MyForm = ({ onSubmit }) =>
      <Autoform
        onSubmit={onSubmit}
        ref={e => formRef = e}
      />

An object with three attributes is exported:

Translation

react-hook-form-auto uses internally a simple better-than-nothing built-in translation system. This system and its translation tables can be replaced and even completely overridden.

The translation strings are hierarchized following some pseudo-semantic rules:

    `models.${model}.${field}.${misc}`

The meaning of the last misc part usually depends on the type of field.

The dots navigates through children in the string table. Example:

    {
      models: {
        computer: {
          cpu: { 
            arm: 'ARM',
            // ...
          },
          // ...
        }
      }
    }

To translate string for your use call tr() and pass the string path separated by dots:

    import { tr } from 'react-hook-form-auto
 
    const message = tr('models.computers.cpu.arm')
 
    /* message value is 'ARM' */

This is the usage of the tr() function:

tr

Translates a string given its id.

Kind: global function
Returns: Translated string

stringExists

Returns if the string does exist

Kind: global function
Returns: boolean - true if it exists

Variable substitution

You can also put variables in the translation strings:

    {
      name: {
        create: '__name__ created'
      }
    }

This allows you to translate and inserting a value in the correct place of the string. Example:

    import { tr } from 'react-hook-form-auto'
 
    const name = 'Alice'
    const message = tr('name.create', { name })
 
    /* message value is 'Alice created' */

Adding strings

    import { addTranslations } from 'react-hook-form-auto'

Then you call addTranslations with the object tree:

addTranslations

Appends translations to current translation table

Kind: global function

It's ok to overwrite a language with another. The non translated strings from the new language will remain from the former in the table. At the moment it's up to you to take care about language completeness (or, better, use an external translator).

Multilanguage

If your application has more than one language and it can be changed on the fly, I better recommend to use translation utils over the core translations. Those functions store the languages separately:

    import { setLanguageByName } from 'react-hook-form-auto'
 
    setLanguageByName('en')

Translation utils

There are some functions that deal with semantic organization of the translation strings this library uses. You can take advantage of them if you are building a skin:

Multipurpose semantic-ish translation.

Kind: global function

Translate field name

Kind: global function

Translates error message.

Kind: global function

Use your own translation system

You can disable the translation system to use your own.

setTranslator

Sets the translation engine that responds to tr().

Kind: global function

Example:

    import { setTranslator } from 'react-hook-form-auto'
    import { myTranslationTranslator } from './serious_translator'
 
    setTranslator((tr, data) => {
      /* do something with tr or data */
 
      return myTranslationTranslator(something, somethingElse)
    })

Or you can drop it directly to setTranslator() if it's compatible.

Extending

Creating a skin

I made a tutorial adapting Material-UI to react-hook-form-auto. You can find it here.

The inputs and auxiliary elements are created using a set of components. The mapping can be set all together by overriding the skin.

You can take a look at defaultSkin.js and components/index.js from any skin to have a glimpse.

There's an entry in the skin object for every field type. The value of the entry is an object with two attributes like in this example:

    number: {
      coerce: value => parseFloat(value),
      render: {
        component: 'input',
        type: 'number'
      }
    },

coerce

Function that converts result to its correct datatype.

render

Properties for the rendered component.

The attribute component is the React component used to render the whole HTML for the input, including label and any other wrappers.

    select: {
      render: {
        component: Select
      }
    },

Object

Props merged to component's default:

    range: {
      coerce: value => parseFloat(value),
      render: {
        component: 'input',
        type: 'range'
      }
    },

Function

Function that takes the component's intended props and returns component's final props:

    string: {
      render: props => ({
        ...props,
        component: props.fieldSchema.textarea ? 'textarea' : 'input'
      }),
    },

Register in render

The component in the render property is also in charge of the field connection with register. For that matter you have two options:

Find a way to pass ref="register" to the final dom element:

  const Input = ({ name, register }) =>
    <MyAwesomeWrapping>
      <input name={name} ref={register} />
    </MyAwesomeWrapping>
 
  const mySkinOverride = {
    string: {
      render: {
        component: Input
      }
    }
  }

Another way is to register manually and call setValue on every change. The component is still uncontrolled but model's value will be updated.

  render: ({ name, register, setValue }) => {
    register({ name })
    const setValueFromEvent = event => {
      setValue(name, event.target.value)
    }
 
    return {
      component: <MyComponent {...} onChange={setValueFromEvent} />
    }
  }

Overriding

You can override (or add) specific types by using <Autoform />'s skinOverride prop.

Skin component

The rest of the properties a skin block can override:

There are also other props passed depending on current implementation of renderInput, the function in charge of choosing the component and render it.

InputWrap

It's a common component used to create all the input structure, including wrappers. You can use it to avoid boilerplate.

The props for the input component are different depending if the inputComponent is a string, like 'input' or a React component.

Native component (ie. 'input')

For a 'lowercase' component like <input />, props passed are

• name
• type
• option (if provided, for the value)
• defaultValue

Class component (ie. MySlider)

Class components receive all the provided or derived props.

Rendering

To render the input or inputs, two functions are used:

renderInputs

Renders the inputs to make the schema work.

Kind: global function
Returns: array - React elements with the form and inputs.

renderInput

Renders a single field.

Kind: global function

Importing base

You can use the base bundle to import AutoformBase component. AutoformBase is like Autoform but doesn't use react-dom dependency.

  import { Autoform, ... } from 'react-hook-form-auto/dist/base.js'

You can also do it in a more permanent way if you use webpack:

  resolve: {
    alias: {
      'react-hook-form-auto': 'react-hook-form-auto/dist/base.js'
    }
  },
 
 
# Help wanted / contribute
 
react-hook-form-auto needs your help. Skins must be written!
 
### Where to begin
 
Make a fork and do your magic followed by a [pull request](https://help.github.com/articles/about-pull-requests/). If it's an implementation, test case and documentation update would be highly appreciated.
 
### Some code pointers
 
Everything is work in progress until there's a bunch of skins or we are in complete control of the world, whichever comes first.
 
The most important files:
 
* `src/ui/components/componentRender.jsx` processes the schema to build the inputs and allows skin overrides
* `src/ui/Autoform.jsx` The component and the coercing logic
* `jsdoc2md/README.hbs` Documentation source
 
See also the [contributing doc](https://github.com/dgonz64/react-hook-form-auto/blob/master/CONTRIBUTING.md).