form

Form

Installation

npm install @react-native-solutions/form

yarn add @react-native-solutions/form

Usage

import { FormProvider, FormAction, useForm, Validators } from '@react-native-solutions/form';

const config = {
  validateOnChange: 'invalid',
  validateOnInit: false,
  fields: {
    login: {
      initialValue: '',
      validate: ({ value }, done, error) => {
        if (!value.includes('@') || !value.includes('+380')) {
          return error('Login is bad :(');
        }

        return done();
      },
    },
    password: {
      initialValue: '',
      validate: (state, done, error) => {
        if (!Validators.email(state)) {
          return error('Some error');
        }

        if (!Validators.maxLength(8)(state)) {
          return error('Password is too long');
        }

        return done();
      },
    },
    privacyPolicy: {
      initialValue: false,
      validate: ({ value }, done, error) => {
        if (!value) {
          return error('This field is required');
        }

        return done();
      },
    },
  },
};

const extractNativeText = ({ nativeEvent: { text } }) => ({
  value: text,
});

function App() {
  const SignInForm = useForm(config);

  const { Fields } = SignInForm;
  return (
    <View style={styles.container}>
      <FormProvider form={SignInForm} onSubmit={console.log}>
        <Fields.LoginField
          render={({ value, handleChange, validation }) => (
            <>
              <TextInput
                style={styles.textField}
                value={value}
                onChange={handleChange(extractNativeText)}
              />
              {!validation.valid && <Text>{validation.errors[0]}</Text>}
            </>
          )}
        />
        <Fields.PasswordField
          render={({ value, handleChange, validation }) => (
            <>
              <TextInput
                style={styles.textField}
                value={value}
                onChange={handleChange(extractNativeText)}
              />
              {!validation.valid && <Text>{validation.errors[0]}</Text>}
            </>
          )}
        />

        <Fields.PrivacyPolicyField
          render={({ value, handleChange, validation }) => (
            <>
              <Switch
                onValueChange={handleChange}
                value={value}
                style={{ width: 20, height: 20 }}
              />
              {!validation.valid && <Text>{validation.errors[0]}</Text>}
            </>
          )}
        />
        <FormAction
          render={(actions: FormStateActions) =>
            actions && <Button title={'Sign In'} onPress={actions.submit} />
          }
        />
      </FormProvider>
    </View>
  );
}

useForm API

Stores form state in a reducer, generates Fields according to given config

See all possible config options in usage example.

const EntireFromState = useForm(config);

const { Fields, state, reset, validate } = EntireFromState;

FormProvider API

Provides a context for Fields & FormAction.

Props:

• form: FormState, result of useForm hook.
• onSubmit: Submit callback.

Field API

Generated field called like configured but in UpperCamelCase. Takes the only one render prop which is a function.

const MyInput = ({ value, handleChange, validation }) => {
    // ...
    return <SomeJSX />
}

<FormProvider form={EntireFormState} onSubmit={handleSubmit}>
    ...
    <Field.MyField render={MyInput} />
    ...
</FormProvider>

• value - field value
• handleChange - a function to change field state, takes a StateExtractor as parameter
• validation - field validation state. Object with valid: boolean and error: string[] properties

State extractors

State extractor is a function which helps to get the desired value from change event.

Takes any event from your input source and must return an object with value property.

Example for react-native TextInput onChange even:

const extractNativeText = ({ nativeEvent: { text } }) => ({
  value: text,
});

// Somewhere in your input
<TextInput onChange={handleChange(extractNativeText)} />

If you haven't passed a StateExtractor to the handleChange it will treat upcoming event like a field value.

<TextInput onTextChange={handleChange} />

// Similar to

<TextInput onTextChange={handleChange(text => ({ value: text }))} />

FormAction API

Form action component.

<FormProvider form={EntireFormState} onSubmit={handleSubmit}>
    ...
    <FormAction
      render={({ submit }) => (
        <Button label="submit" onPress={submit} />
      )}
     />
    ...
</FormProvider>

License

MIT