React Native Hook Form View

This component is high level component that leverage features of react-hook-form. The objective of this component is to helps developer to create form in React Native/Web easily.

Highlight

1. Customizable style & view
2. Easy form validation (leverage on react-hook-form)
3. Support React Native Web

---

Table of contents

• Installation
• Getting Started
  • Simple Usage
  • Advanced Usage
• Props
• Future Roadmap
• Changelog

---

Installation

# using yarn
yarn add react-native-hook-form-view

# using npm
npm install react-native-hook-form-view

---

Getting Started

Simple Usage

import React, { useRef } from "react";
import { TextInput, Button } from "react-native";
import { Form, FormItem, FormRefProps, Submit } from "react-native-hook-form-view";

const Example: React.FC = () => {

  // create ref
  // NOTE: `formRef` previously used for form submission purpose,
  // since v0.0.3 can use `Submit` component within `Form`
  const formRef = useRef<FormRefProps>();

  // =============== EVENTS
  const onSubmit = (values: any) => {
    // do something with `values`
  }

  // =============== VIEW
  return (
    <Form
      // NOTE: `formRef` previously used for form submission purpose,
      // since v0.0.3 can use `Submit` component within `Form`
      ref={formRef}
      onSubmit={onSubmit}
    >
      <FormItem
        label="First Name"
        name="firstName"
        rules={{
          required: "First name is required"
        }}
        caption="some caption to highlight"
        render={({ field: { onChange, value } }) => (
          <TextInput value={value} onChangeText={onChange} />
        )}
      />


      <FormItem
        label="Custom Field"
        name="custom"
        rules={{
          required: "Custom field is required"
        }}
        render={({ field: { onChange, value } }) => (
          // render custom component to handle value, onChange, onBlur, etc manually
          <TextInput value={value} onChangeText={onChange} />
        )}
      />

      {/* legacy usage, can use `Submit` component */}
      <Button
        title="Submit"
        onPress={() => formRef.current?.submit()}
      />

      {/* latest usage since v0.0.3 */}
      <Submit
        title="Custom Text"
      />
    </Form>
  );
};

Below is the preview of above example

Normal	Validated

---

Advanced Usage

• Validation with yup
• Custom Styling / View
  • Custom Styling
  • Custom View
  • Custom View (render function)
• Access form instance

---

Validation with yup

Prerequisite: Install packages to your project with command below

# yarn
yarn add yup @hookform/resolvers

# npm
npm install yup @hookform/resolvers

Always refer to offical documentation for more advanced usage & details. The example below will just be showing minimal working example of how to validate your form with yup.

1. For react-hook-form resolvers, please refer to offical github
2. For yup validation API please refer to official github

import React from "react";
import * as yup from 'yup';
import { useForm } from "react-hook-form";
import { TextInput, View } from "react-native";
import { yupResolver } from '@hookform/resolvers/yup';
import { Form, FormItem, Submit } from "react-native-hook-form-view";

type InputPayload = {
  email: string;
  password: string;
}

// create your validation schema
const schema = yup.object().shape({
  email: yup.string().required('Email is required').email("Invalid email address"),
  password: yup.string().required('Password is required').min(8, "Minimum length is 8 charactors")
});


const SignInForm: React.FC = () => {

  // =============== EVENTS
  const onSubmit = (values: InputPayload) => {
    // do somethoing with `values`
  }

  // =============== VIEW
  return (
    <Form<any, InputPayload>
      options={{
        resolver: yupResolver(schema)
      }}
      onSubmit={onSubmit}
    >
      <FormItem
        label="Email Address"
        name="email"
        render={({ field: { onChange, value } }) => (
          <TextInput value={value} onChangeText={onChange} />
        )}
      />

      <FormItem
        label="Password"
        name="password"
        render={({ field: { onChange, value } }) => (
          <TextInput secureTextEntry value={value} onChangeText={onChange} />
        )}
      />

      {/* latest usage since v0.0.3 */}
      <Submit />
    </Form>
  );
};

---

Custom Styling / View Configuration

The component has come with default styling but if you want to customize the styling or view you're able to do so. Just wrapped your component with NativeFormViewProvider (usually put at entry file eg: app.tsx).

You may refer the section below for more information with examples

• Custom Styling
• Custom View
• Custom View (render function)

Just for your information, the priority of how style being take place would be

Custom View (render function) > Custom Styling > Custom View

Note: Please refer the table below for description & style for each view

View	Description	Style Type	Default Style	Release
container	Form container	ViewStyle	padding: 8px;	v0.0.0
item	Form item container	ViewStyle	padding: 8px;	v0.0.0
label	Form item label text view	TextStyle	color: #111827; font-weight: 400; font-size: 16px; margin-bottom: 4px;	v0.0.0
caption	Form item caption text view	TextStyle	color: #3f3f46; font-weight: 200; font-size: 12px; margin-top: 4px;	v0.0.0
error	Form item error text view	TextStyle	color: #f87171; font-weight: 200; font-size: 12px; margin-top: 4px;	v0.0.0
submit	Submit Button	ViewStyle	margin-top: 4px; background-color: #0ea5e9; padding-vertical: 12px; padding-horizontal: 32px;	v0.0.3

The layout structure

• Orange: container / renderContainer
• Purple: item / renderItem
• Green: label / renderLabel
• Cyan: caption / renderCaption
• Red: error / renderError
• Blue Button submit / renderSubmit (added on v0.0.3)

---

Custom styling

Please be aware that if you specified any style for particular view just like example below, it will actually overwrite its default styling.

import { NativeFormViewProvider } from 'react-native-hook-form-view';

const YourApp: React.FC = () => {
  return (
    <NativeFormViewProvider
      styles={{
        container: {
          backgroundColor: '#0ea5e9',
        },
        item: {
          backgroundColor: '#38bdf8',
          padding: 4,
        },
        label: {
          backgroundColor: '#7dd3fc',
        },
        caption: {
          backgroundColor: '#bae6fd',
        },
        error: {
          backgroundColor: '#e0f2fe',
        },
        submit: { // added on v0.0.3
          backgroundColor: '#ef4444',
        }
      }}
    >
      {/* YOUR COMPONENT*/}
    </NativeFormViewProvider>
  );
};

Custom View

You can have your preferred custom component for specific view. For example below I'll be using styled-components as my custom component

import styled from 'styled-components/native';
import { NativeFormViewProvider } from 'react-native-hook-form-view';

export const CustomFormContainer = styled.View`
  padding: 8px;
  background-color: grey;
  margin-bottom: 8px;
`;

export const CustomFormItemWrapper = styled.View`
  margin-bottom: 8px;
  background-color: yellow;
`;

export const CustomFormItemLabel = styled.Text`
  background-color: green;
  font-weight: 600;
  font-size: 16px;
  margin-bottom: 4px;
`;

export const CustomFormItemCaption = styled.Text`
  background-color: blue;
  padding: 4px;
  color: white;
  font-weight: 200;
  font-size: 12px;
`;

export const CustomFormItemError = styled.Text`
  background-color: #dc2626;
  padding: 4px
  font-weight: 200;
  font-size: 12px;
  color: white;
`;

export const CustomSubmitButton = (props) => {
  // please use `onPress` from `props` in order to trigger form submission
  // or use `useNativeFormContext`, check out "Access form context" for more info
  return (
    <Pressable {...props} style={{ backgroundColor: "red", padding: 20 }}>
      <Text>Submit</Text>
    </Pressable>
  );
};

const YourApp: React.FC = () => {
  return (
    <NativeFormViewProvider
      container={CustomFormContainer}
      item={CustomFormItemWrapper}
      label={CustomFormItemLabel}
      caption={CustomFormItemCaption}
      error={CustomFormItemError}
      submit={CustomSubmitButton} // added on v0.0.3
    >
      {/* YOUR COMPONENT*/}
    </NativeFormViewProvider>
  );
};

Custom View (render function)

In certain extends you might want to have custom view rendering whenever form/field state changes. For example: The field has red border when validation failed.

import { NativeFormViewProvider } from 'react-native-hook-form-view';

const YourApp: React.FC = () => {
  return (
    <NativeFormViewProvider
      renderContainer={({ props, formState }) => {
        return (
          <View style={{ backgroundColor: '#38bdf8' }}>
            {props.children}
          </View>
        );
      }}
      renderItem={({ props, fieldState }) => {
        return (
          <View
            style={{
              borderWidth: fieldState.invalid ? 1 : undefined,
              borderColor: fieldState.invalid ? 'red' : undefined,
              marginBottom: 16,
            }}
          >
            {props.children}
          </View>
        );
      }}
      renderLabel={({ props, fieldState }) => {
        return (
          <Text style={{ backgroundColor: '#bae6fd' }}>
            {props.children}
          </Text>
        );
      }}
      renderCaption={({ props, fieldState }) => {
        return (
          <Text style={{ backgroundColor: '#e0f2fe' }}>
            {props.children}
          </Text>
        );
      }}
      renderError={({ props, fieldState }) => {
        return (
          <Text style={{ backgroundColor: '#f0f9ff' }}>
            {props.children}
          </Text>
        );
      }}
      renderSubmit={({ props, formState }) => { // added on v0.0.3
        return (
          <Button color="#dc2626" title="Submit" disabled={formState.isSubmitting} />
        );
      }}
    >
      {/* YOUR COMPONENT*/}
    </NativeFormViewProvider>
  );
};

---

Access form context

In some case, you might want to access form context in certain extends. The usual way would be passing it as props to the component, but things get complicated & very hard to debug when it deep nested.

By useNativeFormContext hook, you're able to access it with ease.

import { useForm } from "react-hook-form";
import { TextInput, View, Text } from "react-native";

const YourComponent: React.FC = () => {
  const {
    form, // current form context
    submit, // added on v0.0.4, for form submission
  } = useNativeFormContext();

  // example to add form submission triggering
  const triggerSubmitAnywhere = () => {
    submit()
  }

  // do something with the variables above
  return (
    <View>
      <Button title="Do submission from this component" onPress={triggerSubmitAnywhere}>
    <View>
  );
};

Note: By using useNativeFormContext hook, please make sure your component is wrapped under Form or NativeFormContextProvider else you will get error.

---

Props

Form

Props	Type	Value	Description
ref	React Ref (optional)	-	Ref to control form
options	object (optional)	-	Form options (checkout here)
onSubmit	function (optional)	-	Callback function that return form values upon submit

FormItem

Props	Type	Value	Description
name	string	-	The input name
label	string (optional)	-	The label name for the input
caption	string (optional)	-	Caption of the input
control	Control(optional)	-	This object contains methods for registering components into React Hook Form.
rules	object (optional)	-	Validation rules. Checkout here
disabled	boolean (optional)	false	To disabled input (only works if input component has disabled / editable props existed)
initialValue	unknown (optional)	-	initial value (take note on defaultValue )
render	function (optional)	-	A function that returns a React element (checkout render in here)
constructErrorMessage	function (optional)	-	function to contruct error message

NativeFormViewProvider

Checkout the example as it shown all available props

• Custom Styling
• Custom View
• Custom View (render function)

---

Future Roadmap

In near future, will support more preset input from React Native by default. Ideally just passing type as one of the props from FormItem.

import { FormItem } from 'react-native-hook-form-view';

<FormItem type="input" name="firstName" />
<FormItem type="date" name="dob" />
<FormItem type="textarea" name="description" />

• TextInput
• DateInput
• Checkbox
• TextArea
• Switch
• Fields definition with Object
• etc

---

Changelog

0.0.5

• upgrade from React 17 to React 18 & all dependencies
• add comments to code & update coding practices

0.0.4

• add custom inline style for style, labelStyle, captionStyle, errorStyle for FormItem component

• revised v0.0.3 form submission from useNativeFormContext, calling submit function will trigger for form submission. see below example:

  // usage in v0.0.3
  const { form, submitHandler } = useNativeFormContext();
  form?.handleSubmit(submitHandler); // <-- changed this
  
  // usage in v0.0.4
  const { form, submit } = useNativeFormContext();
  submit(); // <-- to this

• add loading indicator to Submit component, also enable loading indicator custom style with loadingStyle & loadingColor

0.0.3

• added StyledPressable, StyleButtonSubmit component as default component

• added Submit component to ease form submission (previously had to called formRef.current?.submit())

  import { Submit } from "react-native-hook-form-view"; // import
  
  // usage
  <Form onSubmit={onSubmit}>
    <Submit />
  </Form>;

• enable custom Submit button view & style customization on NativeFormViewProvider

• add submitHandler props to useNativeFormContext to provide alternative form submission with hooks

  // usage with `useNativeFormContext`
  const { form, submitHandler } = useNativeFormContext();
  form?.handleSubmit(submitHandler); // call the submit function

0.0.2

• apply FieldValues types for Form & FormItem component

0.0.1

• Update docs

0.0.0

• initial release