Accordion

Install

$ npm install @rynpsc/accordion

Getting Started

HTML

The accordion library tries to impose as few structural HTML requirements as possible. The minimum required HTML structure is as follows:

1. A containing element with a valid id attribute.
2. Pairs of header and panel elements whose relationship is described by the data-for attribute on the header element, its value is the id of the related panel.

<div id="example">
  <h2 data-accordion-for="panel-one">Panel One</h2>
  <div id="panel-one">...</div>

  <h2 data-accordion-for="panel-two">Panel Two</h2>
  <div id="panel-two">...</div>
</div>

JavaScript

The accordion constructor takes two parameters:

• id - The ID of the containing element
• options - An optional options object

import { accordion } from '@rynpsc/accordion';

let instance = accordion('example', {
  multiselect: true,
});

if (instance) {
  instance.init();
}

CSS

The library takes care of hiding and showing panels via display none and block.

Animation

To enable animating the opening and closing of a panel set the animate option to true and add a CSS height transition to the panel.

.panel {
  transition: height 200ms ease-in-out;
}

Padding and Animation

To animate a panel that has padding it is recommended to apply the padding to a child element.

<div class="panel" id="panel-one">
  <div class="panel-inner"></div>
</div>

.panel {
  transition: height 200ms ease-in-out;
}

.panel-inner {
  padding: 20px;
}

API

accordion(id, options)

• id: string
• options: Options
• Returns: Accordion | undefined

Creates an Accordion instance.

If the passed in id doesn't match an element in the DOM, undefined is returned. Therefore, it is recommended to add a check before calling any properties or methods.

import { accordion } from '@rynpsc/accordion';

let instance = accordion('example', options);

if (instance) {
  instance.init();
}

instances

An Object containing all the current Accordion instances indexed by the containing elements id.

import { instances } from '@rynpsc/accordion';

for (let [ id, instance ] of Object.entries(instances)) {
  console.log(id, instance);
}

getInstanceById(id)

Helper method for getting an Accordion instance by its id.

• id: string
• Returns: Accordion | undefined

import { getInstanceById } from '@rynpsc/accordion';

let instance = getInstanceById('accordion');

if (instance) {
  instance.openAll();
}

Accordion

id

The id passed into the accordion constructor.

• Type: string

root

The element that matches the id passed into the accordion constructor.

• Type: HTMLElement

items

An Array of AccordionItem Objects.

getItem(target)

Gets an accordion item by either its numerical index or id.

• target: string | number
• Returns: AccordionItem | undefined

instance.getItem('panel-one');

init()

Initialises the instance.

• Returns: void

instance.init();

If calling init after calling destroy any event listeners will need to be re-registered.

destroy()

Restores the DOM changed in the init method and removes any registered event listeners added via the on method.

• Returns: void

instance.destroy();

open(target, options)

Open a panel by either its numerical index or ID.

• target: string | number
• options Object
  • animate - Animate the height, by default is the same as the global animate option.

instance.open(0);

instance.open('panel-one', {
  animate: true
});

An array can also be provided to open multiple panels.

instance.open(['panel-one', 'panel-two']);

close(target, options)

Close a panel by either its numerical index or ID.

• target: string | number
• options Object
  • animate - Animate the height, by default is the same as the global animate option.

instance.close(0);

instance.open('panel-one', {
  animate: true
});

An array can also be provided to close multiple panels.

instance.close(['panel-one', 'panel-two']);

toggle(target, options)

Toggle a panel between opened and closed by either its numerical index or ID.

• target: string | number
• options Object
  • animate - Animate the height, by default is the same as the global animate option.

instance.toggle(0);

instance.toggle('panel-one', {
  animate: true
});

openAll()

Open all panels.

instance.openAll();

closeAll()

Close all panels.

instance.closeAll();

enable()

Enable a panel, allowing it to be opened and closed.

instance.enable('panel-one');

disable()

Disable a panel, preventing it from being opened and closed.

instance.disable('panel-one');

on(type, listener)

Adds an event listener, see events.

instance.on('open', function(event) {
  console.log(event.detail);
});

off(type, listener)

Removes an event listener, see events.

instance.off('open', function(event) {
  console.log(event.detail);
});

AccordionItem

A header/panel pair is represented by an AccordionItem.

id

The item id, this is the id used to link the header and panel.

• Type: string

header

The element with the associated data-for attribute.

• Type: HTMLElement

button

The button that controls the opening and closing of the associated panel.

• Type: HTMLButtonElement

panel

The element associated with the control.

• Type: HTMLElement

active

Indicates if the item is open.

• Type: boolean

disabled

Indicates if the item is disabled.

• Type: boolean

enable()

Enable the item, allowing it to be opened and closed.

• Returns: void

disable()

Disable the item, disallowing it to be opened and closed.

• Returns: void

open(options)

Open the items panel.

• Returns: void

Options:

• animate: boolean

close(options)

Close the items panel.

• Returns: void

Options:

• animate: boolean

Options

initialisedClass

Class to add to root element on initialisation.

• Type: string | undefined
• Default: ''

activePanelClass

Class to add to the active panel.

• Type: string
• Default: ''

activeHeaderClass

Class to add to the active header.

• Type: string
• Default: ''

headerButtonClass

Class to add to the generated header button.

• Type: string
• Default: ''

animate

Animate the opening and closing of panels.

• Type: boolean
• Default: true

multiselect

Allow multiple panels to be expanded at once.

• Type: boolean
• Default: true

prefix

Prefix to use for data attributes e.g data-prefix-for.

• Type: string
• Default: accordion

Events

Events are handled via the CustomEvent API. For some events additional event information is available via event.detail.

Name	Description	Detail	Cancelable
open	Dispatched when a panel is opened	AccordionItem	Yes
close	Dispatched when a panel is closed	AccordionItem	Yes
enable	Dispatched when a panel is enabled	AccordionItem	Yes
disable	Dispatched when a panel is disabled	AccordionItem	Yes
create	Dispatched when the accordion is created	null	No
destroy	Dispatched when the accordion is destroyed	null	No

instance.on('open', function(event) {
  console.log(event.detail.active) // true
})

Canceling Events

Cancelable events can be canceled by calling event.preventDefault().

instance.on('open', function(event) {
  event.preventDefault();
});

Requirements

This package is written and distributed in ES module format, as well as commonjs and umd for legacy support. It is written using ES2020 syntax and features, and requires the following browser APIs:

• CustomEvent
• Element.classList
• HTMLOrForeignElement.dataset
• Element.querySelectorAll
• Window.requestAnimation

ES module format should be the preferred format for consuming. If using umd you'll need to use accordion.accordion, accordion.instances and accordion.getInstanceById.

License

MIT