A modular DOM helper library.

npm install domestique

Note: This library is written as ES2015 code and published as such to npm. Read the Compatibility section for more information.

import {
     // Dimension
    inViewport,
    scrollbarSize,
    viewportHeight,
    viewportWidth,

    // Element
    activeElement,
    create,
    addClass,
    removeClass,
    hasClass,
    data,
    focus,
    isFocusable,
    isTabbable,
    parents,
    render,

    // Event
    delegate,
    dispatch,
    on,
    onTransitionEnd,
    off,
    ready,

    // Query
    closest,
    find,
    focusable,
    matches,
    select,
    selectAll,
    tabbable
} from 'domestique';

• Dimension
  • inViewport()
  • scrollbarSize()
  • viewportHeight()
  • viewportWidth()
• Element
  • activeElement()
  • create()
  • addClass()
  • removeClass()
  • hasClass()
  • data()
  • focus()
  • isFocusable()
  • isTabbable()
  • parents()
  • render()
• Event
  • delegate()
  • dispatch()
  • on()
  • onTransitionEnd()
  • off()
  • ready()
• Query
  • closest()
  • find()
  • focusable()
  • matches()
  • select()
  • selectAll()
  • tabbable()

inViewport(element: Element): bool

Returns true if any part of an element is in the viewport.

const inVp = inViewport(element);

scrollbarSize(): number

Returns the size of the scrollbar in pixels.

const size = scrollbarSize();

viewportHeight(): number

Returns the viewport height.

Note: The height represent the CSS viewport height (@media (height)) including the size of a rendered scroll bar (if any).

const vpHeight = viewportHeight();

viewportWidth(): number

Returns the viewport width.

Note: The width represent the CSS viewport width (@media (width)) including the size of a rendered scroll bar (if any).

const vpWidth = viewportWidth();

activeElement(): Element

Returns the element that currently has focus.

const element = activeElement();

create(html: string): Element

Creates a DOM element from a HTML string. If it's already a DOM node, the node is returned as is.

const element = create('<div/>');

addClass(element: Element, className: string): void

Adds a class (or multiple classes separated by space) to an element.

addClass(element, 'my-class');
addClass(element, 'my-class my-other-class');

removeClass(element: Element, className: string): void

Removes a class (or multiple classes separated by space) from an element.

removeClass(element, 'my-class');
removeClass(element, 'my-class my-other-class');

hasClass(element: Element, className: string): bool

Checks whether an element has a class (or multiple classes separated by space).

const hasClass = hasClass(element, 'my-class');
const hasAllClasses = hasClass(element, 'my-class my-other-class');

data(element: Element, name: string): bool

Reads and parses data from an data-* attribute.

<div
   data-string="string"
   data-true="true"
   data-false="false"
   data-null="null"
   data-integer="1"
   data-float="1.2"
   data-json-object="{&quot;foo&quot;: &quot;bar&quot;}"
   data-json-array="[&quot;foo&quot;]"
></div>

const stringValue = data(element, 'string');
const trueValue = data(element, 'true');
const falseValue = data(element, 'false');
const nullValue = data(element, 'null');
const integerValue = data(element, 'integer');
const floatValue = data(element, 'float');
const jsonObjectValue = data(element, 'json-object');
const jsonArrayValue = data(element, 'json-array');

focus(element: Element[, options: object]): void

Shifts focus to an element.

focus(element);

Browsers scroll the focused element into view. focus() provides an option restoreScrollPosition to restore scroll positions of all scroll containers of the focused element to the state before the element got focus.

focus(element, {
    restoreScrollPosition: true
});

isFocusable(element: Element): bool

Checks whether an element is focusable.

Unlike isTabbable(), the function also returns true for elements which are not focusable by the keyboard, but only by script (element.focus()) and possibly the mouse (or pointer). Usually, those are elements with a negative tabindex attribute value, like -1.

const isFocusableElement = isFocusable(element);

isTabbable(element: Element): bool

Checks whether an element is tabbable.

Unlike isFocusable(), the function returns true only for elements which are focusable by the keyboard (by pressing the TAB and SHIFT TAB keys). Elements that are only focusable by script (element.focus()) and possibly the mouse (or pointer) are excluded.

const isFocusableElement = isFocusable(element);

parents(element: Element): Array

Returns an array of the element's parent elements.

const parentElements = parents(element);

render(html: string): object

Creates and returns DOM element references from a HTML string.

Elements must have a ref attribute with the reference name. The value of this attribute will get mapped to the property name of the returned object.

const {list, 'list-items': listItems} = render(`
<ul ref="list">
    <li ref="list-items[]"></l>
    <li ref="list-items[]"></l>
</ul>
`);

Note: The ref attributes will be removed from the returned elements.

delegate(target: EventTarget, type: string, selector: string, listener: EventListener[, options: object]): function

Registers a listener for the event type on target with options that processes events from descendant elements of target matching the specified selector.

The function returns another function which can be used to unregister the event listener.

const listener = function (e, target) {
    target.classList.add('my-target-clicked');

    console.log('My Button clicked');
};
const options = {
    passive: true
};

const remove = delegate(
    document, // Listen on document
    'click',
    '.my-button',
    listener,
    options
);

remove(); // Remove event listener

dispatch(target: EventTarget, type: string[, eventInit: CustomEventInit]): bool

Dispatches a CustomEvent type at the specified target optionally using the eventInit options.

The function returns false if the event is cancelable and at least one of the event handlers which handled this event called Event.preventDefault(). Otherwise it returns true.

const clickNotCancelled = dispatch(document, 'click');

const myEventNotCancelled = dispatch(
    document.querySelector('.my-button'),
    'my:event',
    {
        bubbles: true,
        cancelable: true,
        detail: {
            foo: 'bar'
        }
    }
);

on(target: EventTarget, type: string, listener: EventListener[, options: object]): function

Registers a listener for the event type on target with options.

options is always an object that specifies characteristics about the event listener, see https://developer.mozilla.org/docs/Web/API/EventTarget/addEventListener.

If one of the options isn't supported by the browser, the behavior is as follows:

• capture: Always supported.
• once: Will be polyfilled.
• passive: Will be ignored.

The function returns another function which can be used to unregister the event listener.

const target = document.querySelector('.my-button');
const listener = function () {
    console.log('My Button clicked');
};
const options = {
    once: true
};

const remove = on(
    target, 
    'click',
    listener,
    options
);

remove(); // Remove event listener

onTransitionEnd(target: EventTarget, listener: EventListener): function

Registers a one-time listener for the transitionend event on target.

The function returns another function which can be used to unregister the event listener.

const target = document.querySelector('.my-element');
const listener = function (target) {
    target.classList.add('transition-ended');

    console.log('Transition ended');
};

const remove = onTransitionEnd(
    target,
    listener
);

remove(); // Remove event listener

off(target: EventTarget, type: string, listener: EventListener[, options: object]): void

Removes a listener previously registered via on().

off(
    target, 
    'click',
    listener,
    options
);

ready(listener: function): void

Registers a listener to be called once the DOM is ready.

Unlike DOMContentLoaded, this also works when called after the DOM was loaded.

ready(function () {
    console.log('DOM is ready!');
});

closest(element: Element, selector: string): Element

Returns the closest ancestor of the element (or the element itself) which matches the specified selector.

If there isn't such an ancestor, it returns null.

const closestParagraph = closest(element, 'p');

Deprecated in favor of selectAll(). To be removed in 2.0.

find(selector: string[, element: Element]): array

Returns an array of elements matching the specified selector which are descendants of the document or the element specified as optional second argument.

const paragraphs = find('p');

const spansInsideFirstParagraph = find('span', paragraphs[0]);

focusable([element: Element]): array

Returns an array of focusable elements in the DOM which are descendants of the document or the element specified as optional first argument.

Unlike tabbable(), the array also includes elements which are not focusable by the keyboard, but only by script (element.focus()) and possibly the mouse (or pointer). Usually, those are elements with a negative tabindex attribute value, like -1.

Note: The elements in the array are ordered according to the sequential focus navigation order which may be different from the DOM order.

const focusableElements = focusable();

matches(element: Element, selector: string): boolean

Returns true if the element would be selected by the specified selector, false otherwise.

const isParagraph = matches(element, 'p');

select(context: Element, selector: string): Element

Returns the descendant of context (document or Element) which matches the specified selector. If no element could be found, null is returned.

const paragraph = select(document, 'p');

const spanInsideParagraph = select(paragraph, 'span');

select(context: Element, selector: string): array

Returns an array of all descendants of context (document or Element) which match the specified selector.

const allParagraphs = selectAll(document, 'p');

const allSpansInsideFirstParagraph = selectAll(paragraph[0], 'span');

tabbable([element: Element]): array

Returns an array of keyboard focusable ("tabbable") elements in the DOM which are descendants of the document or the element specified as optional first argument.

Unlike focusable(), the array only includes elements which are focusable by the keyboard (by pressing the TAB and SHIFT TAB keys). Elements that are only focusable by script (element.focus()) and possibly the mouse (or pointer) are excluded.

Note: The elements in the array are ordered according to the sequential focus navigation order which may be different from the DOM order.

const tabbableElements = tabbable();

This library is written as ES2015 code and published as such to npm. It is compatible with modern browsers which natively support <script type="module">.

If support for older browsers is required, code from domestique must be transpiled, eg. by using Babel.

Most bundlers (like Webpack and Rollup) recommend to not transpile anything from the node_modules/ directory. It must be ensured, that code from domestique is not excluded from transpilation.

If you're using Webpack and Babel, that could look like:

{
    module: {
        rules: [
            {
                test: /\.js$/,
                exclude: /node_modules\/(?!domestique)/,
                loader: 'babel-loader'
            }
        ]
    }
}

After transpilation, domestique supports the most common browsers including IE 10 without polyfills.

• BrowserStack for providing free VMs for automated testing.
• GitHub for providing free Git repository hosting.
• npm for providing the package manager for JavaScript.
• TravisCI for providing a free build server.

Copyright (c) 2018-2021 Jan Sorgalla. Released under the MIT license.