The companion for Web forms!

Extract and set form values through the DOM—no frameworks required!

Lightweight. Simple. It Just Works.

Installation

The package can be found on:

• Modal Pack
• npm
• GitHub Package Registry

Usage

1. Lay out your input elements (all valid input types supported including <select> and <textarea>) then bind them to a form:
   • Put them inside a <form>.
   • Alternatively, use the form="" attribute then specify the form id where they will be bound.
2. Add name="" attributes to your input elements.
3. Get your <form> element:
   • Query the form directly.
   • If you want to retrieve/set the form values through an individual input element (e.g. in the case of value change events like onchange), use the inputElement.form attribute.
4. Use getFormValues() to retrieve all bound input elements’ values, or setFormValues() to set them (setting only some fields’ values is supported).

Example

For an example form:

<form id="loginForm" aria-label="Login Form">
  <button id="autofill" type="button">
    Autofill login form (username: admin)
  </button>
  
  <hr />
  
  <fieldset>
    <legend>
      Login
    </legend>
    <div>
      <input type="text" name="username" placeholder="Username" />
    </div>
    <div>
      <input type="password" name="password" placeholder="Password" />
    </div>
    <div>
      <button type="submit" name="type" value="client">
        Log In As Client
      </button>
      <button type="submit" name="type" value="admin">
        Log In As Admin
      </button>
    </div>
  </fieldset>
</form>

<!-- Input elements can be placed outside the form element they are bound to. -->

<label>
  <input type="checkbox" name="remember" form="loginForm" />
  Remember my login credentials
</label>

Use the library as follows (code is in TypeScript, but can work with JavaScript as well):

import { getFormValues, setFormValues } from '@theoryofnekomata/formxtra';

// This is the only query we need. On libraries like React, we can easily get form elements when we
// attach submit event listeners.
const form: HTMLFormElement = document.getElementById('form');

const processResponse = async (response: Response) => {
  const result = await response.json();

  alert(`Welcome ${result.user}!`);
};

// Best use case is with event handlers
form.addEventListener('submit', async e => {
  const {
    currentTarget: thisForm,
    submitter,
  } = e;
  e.preventDefault();

  const values = getFormValues(thisForm, { submitter });

  // Get the form values and send as request to some API
  const response = await fetch(
    'https://example.com/api/log-in',
    {
      method: 'POST',
      body: JSON.stringify(values),
      headers: {
        'Content-Type': 'application/json',
      },
    },
  );

  if (response.ok) {
    processResponse(response);
  }
});

// You can use fomrxtra directly with elements as long as they are bound to a form.
const autofillButton = document.getElementById('autofill');

autofillButton.addEventListener('click', e => {
  setFormValues(e.currentTarget.form, { username: 'admin', remember: true });
});

There are utility functions exported alongside getFormValues() and setFormValues(). You may want to use namespace import with this library, i.e. import * as formxtra from '@theoryofnekomata/formxtra'.

See the documentation folder for more details.

Tests

The library has been tested on the static DOM using JSDOM, and the real dynamic DOM using Cypress.

License

MIT