.. Copyright (C)  2016 Champs Libres Cooperative SCRLFS
   Permission is granted to copy, distribute and/or modify this document
   under the terms of the GNU Free Documentation License, Version 1.3
   or any later version published by the Free Software Foundation;
   with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts.
   A copy of the license is included in the section entitled "GNU
   Free Documentation License".


Javascript functions
####################

Some function may be useful to manipulate elements on the page.

Show-hide elements according to a form state
*********************************************

The module ``ShowHide`` will allow you to show/hide part of your page using a specific test.

This must be use inside a javascript module.

Usage
=====

In this module, the module will listen to all input given in the ``container_from`` div, and will show or hide the content of the ``container_target`` according to the result of the ``test`` function.

.. code-block:: html+twig

		<div id="container_from">
			{{ form_row(form.accompagnementRQTHDate) }}
		</div>
		
		<div id="container_target">
			{{ form_row(form.accompagnementComment) }}
		</div>

.. code-block:: javascript

    import { ShowHide } from 'ShowHide/show_hide.js';

    var 
        from = document.getElementById("container_from"),
        target = document.getElementById("container_target")
        ;

    new ShowHide({
        froms: [from], // the value of from should be an iterable
        container: [ressources_comment], // the value of container should be an iterable
        test: function(froms, event) {
            // iterate over each element of froms
            for (let f of froms.values()) {
                // get all input inside froms
                for (let input of f.querySelectorAll('input').values()) {
                    if (input.value === 'autre') {
                        return input.checked;
                    }
                }
            }

            return false;
        }
    });

Once instantiated, the class ``ShowHide`` will:

1. get all input from each element inside the ``froms`` values
2. attach an event listener (by default, ``change``) to each input inside each entry in ``froms``
3. each time the event is fired, launch the function ``test``
4. show the element in the container given in ``container``, if the result of ``test`` is true, or hide them otherwise.

The test is also launched when the page is loaded.

Show/hide while the user enter data: using the ``input`` event
==============================================================

One can force to use another event on the input elements, instead of the default ``'change'`` event. 

For achieving this, use the `event_name` option.

.. code-block:: javascript 

    new ShowHide({
        froms: froms,
        test: test_function,
        container: containers ,
        // using this option, we use the event `input` instead of `change`
        event_name: 'input'
    });

Examples
========

.. literalinclude:: js-functions/show_hide.js
   :language: javascript