LemonadeJS Object Forms

LemonadeJS Object Forms simplify form handling by linking form elements to a JavaScript object using the setPath method. Updates on the element values update the object path value automatically, while object changes can be applied to the form using setForm. It’s perfect for managing complex, nested data structures without manual DOM manipulation.

How It Works

The setPath method creates a reactive form object and a function to update form values. You define an initial object and an optional callback to handle changes. Form elements tagged with lm-path (or :path) map to properties in the object using dot notation (e.g., options.mask). When a form element’s value changes, the object updates automatically. To update the form with new object values, call setForm.

Key Features

Reactive Updates: Form inputs update the object instantly.
Programmatic Control: Use setForm to sync object changes to the form.
Nested Objects: Supports deep paths like options.mask for complex data.
Callback Support: Run custom logic when form values change.
Flexible Inputs: Works with text inputs, dropdowns, checkboxes, and custom components.

Documentation

setPath

Method Description

setPath @param {any} initial - Initial object with form values.
@param {Function} callback - Optional function triggered when a form element updates the object. Receives value, path, and element as arguments.
@return [form, setForm] - Array containing the reactive form object and the setForm function to update form values.
setPath(initial: any, callback?: (value: any, path: string, element: HTMLElement) => void) => [object, Function]

Method	Description
`setPath`	`@param {any} initial` - Initial object with form values. `@param {Function} callback` - Optional function triggered when a form element updates the object. Receives `value`, `path`, and `element` as arguments. `@return [form, setForm]` - Array containing the reactive form object and the `setForm` function to update form values. `setPath(initial: any, callback?: (value: any, path: string, element: HTMLElement) => void) => [object, Function]`

lm-path / :path

Attribute	Description
`lm-path`	Specifies the dot-notated path in the form object (e.g., `title`, `options.mask`). Binds the element’s value to that path.

Example

The form object holds the values of your form, and setForm applies new values to the form elements based on the defined lm-path attributes.

<html>
<script src="https://lemonadejs.com/v5/lemonade.js"></script>
<div id='root'></div>
<script>

const { setPath } = lemonade;

function Component() {
    let properties = {
        options: {
            mask: 123,
        },
        title: 'Test',
    };

    let [data, setData] = setPath(properties, (value, path, element) => {
        console.log(`Updated ${path} to ${value}`);
    });

    const save = () => {
        // send data to the server to persist the form information
        console.log('Form data:', data);
    };

    return render => render`<div>
        <div class='lm-row'>
            <div class='lm-column lm-f1'>
                <div class='lm-form-group'>
                    <label>Header Title</label>
                    <input type='text' lm-path="title" />
                </div>
            </div>
        </div>
        <div class='lm-row'>
            <div class='lm-column lm-f1'>
                <div class='lm-form-group'>
                    <label>Mask</label>
                    <input type='text' placeholder="#.##0,00" lm-path="options.mask" />
                </div>
            </div>
        </div>
        <div class='lm-row'>
            <input type="button" value="Save" onclick="${save}" />
        </div>
    </div>`;
}

lemonade.render(Component, document.getElementById('root'));
</script>
</html>

import { setPath } from 'lemonadejs';

export default function Test() {
    let properties = {
        options: {
            mask: 123,
        },
        title: 'Test',
    };

    let [data, setData] = setPath(properties, (value, path, element) => {
        console.log(`Updated ${path} to ${value}`);
    });

    const save = () => {
        // send data to the server to persist the form information
        console.log('Form data:', data);
    };

    return render => render`<div>
        <div class='lm-row'>
            <div class='lm-column lm-f1'>
                <div class='lm-form-group'>
                    <label>Header Title</label>
                    <input type='text' lm-path="title" />
                </div>
            </div>
        </div>
        <div class='lm-row'>
            <div class='lm-column lm-f1'>
                <div class='lm-form-group'>
                    <label>Mask</label>
                    <input type='text' placeholder="#.##0,00" lm-path="options.mask" />
                </div>
            </div>
        </div>
        <div class='lm-row'>
            <input type="button" value="Save" onclick="${save}" />
        </div>
    </div>`;
}

What's Next?

Learn more about how LemonadeJS manages arrays and dynamic loops in the next section.

Dynamic Loops from Arrays

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