0.0.3 • Public • Published

Deep Focus Trap

Getting Started

  1. Install library using

    $ npm install deep-focus-trap
  2. Import library

    import { focusTrap } from 'deep-focus-trap';
  3. Initalize class with config options:

     const focusTrap = new focusTrap({
       el: '.modal'
  4. Activate the focus trap when you need to trap focus with the element (i.e. when a user opens a modal).

  5. Then deactivate when you no longer need to trap focus (i.e. when a user closes the modal).



import { focusTrap } from 'deep-focus-trap/dom'

const query = (selector) => document.querySelector(selector);
const modal = query('.modal')
const openModalBtn = query('.open-modal-btn');
const closeModalBtn = query('.close-modal-btn');
const focusTrap = new focusTrap({
  el: '.modal',
  escCallback: function (){ = 'none';

//open modal event
openModalBtn.onclick = function(){ = 'block';

//close modal event
closeModalBtn.onclick = function(){ = 'none';

Piercing the Shadow DOM

The main import has two classes for import deepFocusTrap and its parent focusTrap. If you don't need to pierce the shadow DOM you should import the parent class from the dom module (i.e. import { focusTrap } from 'deep-focus-trap/dom'). This reduces the module size significantly as you won't import the dependency required to pierce the shadow DOM. The class that pierces the shadow DOM is deepfocusTrap. You can use this class by importing it from the main module like so: import { deepFocusTrap } from 'deep-focus-trap'.

Both focusTrap and deepFocusTrap have the same functionality and work in the same way except deepFocusTrap is able to pierce the shadow DOM. The reasons there are two classes broken into different modules is to enable tree-shaking, which greatly reduces the imported bundle size (850B compared to 12.5KB minified & gzipped) when you only need the regular focusTrap and don't need to pierce the shadowDOM.

If your project is already using the deepFocusTrap class in other places you are already going to import the extra dependency so you can import the focusTrap class from the main module (i.e. import { focusTrap } from 'deep-focus-trap') or you can use the deepFocusTrap class and set the config.deep option to false. Like so:

import { deepFocusTrap } from 'deep-focus-trap';

let focusTrap = new deepFocusTrap({
  el: '.modal',
  deep: false

Configuration Options

import { deepFocusTrap } from 'deep-focus-trap';
const modal = document.querySelector('.modal');

let focusTrap = new deepFocusTrap({
  el: modal, // or '.modal', Required option - A selector or element used to trap focus within
  deep: false, //default: true - When set to false focusTrap will not peirce the Shadow DOM.
  returnFocus: false, //default: true - An option when set to true returns focus upon deactivation to the last element that had focus before the trap was activated. 
  focusElement: document.querySelector('a.first-focus'), // An element to focus on as soon as the focus trap is activated.
  includeActiveElement: true, //default: false -  Includes element currently in focus when focusTrap is activated within the focusable elements.
  unordered: true, //default: false - Allows for elements to be in an order in the dom. Then follows the order of appearance in the focusableElements array instead.
  escCallback: function(){ // A callback to be called when the user presses the escape key. Note his automatically calls deactivate() after escCallback = 'none';

*Note: the focusTrap class doesn't have the deep option

Using UMD version via CDN

If you want to use via deep-focus-trap via the script tag. We recommend using the UMD version as its more widely supported (You can also use the ES module version using the type="module attribute.") You can find the CDN scripts here

In using the UMD version you wont import the module but just copy the script tag:

<script src="/deep-focus-trap.umd.js"></script>

Or if you want the basic version (doesn't pierce the shadow DOM)

<script src="/focus-trap.umd.js"></script>

Then to use. Use the focusTrap or deepFocusTrap function (umd exports to the window)

const focusTrap = deepFocusTrap({
  el: '.modal',
  escCallback: () => { 
    const modal = document.querySelector('.modal'); = 'none';

You can view the API documentation here


npm i deep-focus-trap

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  • seanbeyond