Hook based form

Installation

$ yarn add @sharingapples/form

Usage

import {
  Form, Group, Array, useFormInput, useFormSubmit, useFormValue, useFormValidator,
} from '@sharingapples/form';

function required(v) { if (v.length === 0) throw new Error('Value is required'); };
function pipe(...validators) {
  return (value) => {
    validators.reduce((res, valitaor) => validator(value), true);
  }
}

function TextInput({ name, label, validators }) {
  const [value, onChange] = useFormInput(name);
  const error = useFormValidator(name, pipe(...validators));
  function handleChange = useCallback((e) => {
    onChange(e.target.value);
  }, []);


  return (
    <div>
      <label>{label}</label>
      <input type="text" value={value} onChange={handleChange} />
      {error && <span className="error">{error}</span>}
    </div>
  );
}

function Submit({ label }) {
  const submit = useFormSubmit();
  return <button onClick={submit}>{label}</button>
}

export default function CustomForm() {
  function handleSubmit(state) {
    // Perform your api invokation here for data structure
    // state = { personal: { name: '', dob: '' }, job: { company: '' }}
  }

  return (
    <Form onSubmit={handleSubmit}>
      <Group name="personal">
        <TextInput name="name" />
        <TextInput dob="dob" />
      </Group>
      <Group name="job">
        <TextInput name="company" />
      </Group>
      <Submit />
    </Form>
  );
}

API

Form

A top level component that keep tracks of the entire form data.

Props

• onSubmit: A required callback handler for processing submitted data
• defaultValue: A default value to prepopulate the form

Group

A component that keep tracks of an object data structure. Can also act as a page within a form with its own onSubmit handling

Props

• name: Name for the data structure
• onSubmit: If a submit button is included within the Group, the changes to the data within the group are not reflected back until the submit with proper validation. The onSubmit method is invoked after the data has been validated successfully.

ArrayGroup

Not documented yet

useFormInput

A hook to declare a form input that is connected with the data structure. This hooks works similar to useState hook, where the state is maintained by the closest Group or Form element.

Parameters

• name: Name within the current data structure to bind to
• defaultValue: A default value to use, if none found within the data structure.

useFormValue

A hook to extract a named value within the data-structure.

parameters

• name: Name within the current data structure to bind to
• context: Used in conjuction with useFormParent to move through the data structure hierarchy.

useFormValidator

A hook for validating data as it changes.

Parameters

• name: A string that would listen to the named value within the current data structure or a mapping function that returns the validation value.
• validator: A function that throws an error checking the validation value, or a string that acts as an error message for a falsy validation value.

useFormSubmit

A hook for getting a submit method to be called from Submit buttons.