/**
* Extend object a with the properties of object b.
* If there's a conflict, object b takes precedence.
*
* @param {object} a
* @param {object} b
*/
export const extend = ( a, b ) => {
for( let i in b ) {
a[ i ] = b[ i ];
}
return a;
}
/**
* querySelectorAll but returns an Array.
*/
export const queryAll = ( el, selector ) => {
return Array.from( el.querySelectorAll( selector ) );
}
/**
* classList.toggle() with cross browser support
*/
export const toggleClass = ( el, className, value ) => {
if( value ) {
el.classList.add( className );
}
else {
el.classList.remove( className );
}
}
/**
* Utility for deserializing a value.
*
* @param {*} value
* @return {*}
*/
export const deserialize = ( value ) => {
if( typeof value === 'string' ) {
if( value === 'null' ) return null;
else if( value === 'true' ) return true;
else if( value === 'false' ) return false;
else if( value.match( /^-?[\d\.]+$/ ) ) return parseFloat( value );
}
return value;
}
/**
* Measures the distance in pixels between point a
* and point b.
*
* @param {object} a point with x/y properties
* @param {object} b point with x/y properties
*
* @return {number}
*/
export const distanceBetween = ( a, b ) => {
let dx = a.x - b.x,
dy = a.y - b.y;
return Math.sqrt( dx*dx + dy*dy );
}
/**
* Applies a CSS transform to the target element.
*
* @param {HTMLElement} element
* @param {string} transform
*/
export const transformElement = ( element, transform ) => {
element.style.transform = transform;
}
/**
* Element.matches with IE support.
*
* @param {HTMLElement} target The element to match
* @param {String} selector The CSS selector to match
* the element against
*
* @return {Boolean}
*/
export const matches = ( target, selector ) => {
let matchesMethod = target.matches || target.matchesSelector || target.msMatchesSelector;
return !!( matchesMethod && matchesMethod.call( target, selector ) );
}
/**
* Find the closest parent that matches the given
* selector.
*
* @param {HTMLElement} target The child element
* @param {String} selector The CSS selector to match
* the parents against
*
* @return {HTMLElement} The matched parent or null
* if no matching parent was found
*/
export const closest = ( target, selector ) => {
// Native Element.closest
if( typeof target.closest === 'function' ) {
return target.closest( selector );
}
// Polyfill
while( target ) {
if( matches( target, selector ) ) {
return target;
}
// Keep searching
target = target.parentNode;
}
return null;
}
/**
* Handling the fullscreen functionality via the fullscreen API
*
* @see http://fullscreen.spec.whatwg.org/
* @see https://developer.mozilla.org/en-US/docs/DOM/Using_fullscreen_mode
*/
export const enterFullscreen = element => {
element = element || document.documentElement;
// Check which implementation is available
let requestMethod = element.requestFullscreen ||
element.webkitRequestFullscreen ||
element.webkitRequestFullScreen ||
element.mozRequestFullScreen ||
element.msRequestFullscreen;
if( requestMethod ) {
requestMethod.apply( element );
}
}
/**
* Creates an HTML element and returns a reference to it.
* If the element already exists the existing instance will
* be returned.
*
* @param {HTMLElement} container
* @param {string} tagname
* @param {string} classname
* @param {string} innerHTML
*
* @return {HTMLElement}
*/
export const createSingletonNode = ( container, tagname, classname, innerHTML='' ) => {
// Find all nodes matching the description
let nodes = container.querySelectorAll( '.' + classname );
// Check all matches to find one which is a direct child of
// the specified container
for( let i = 0; i < nodes.length; i++ ) {
let testNode = nodes[i];
if( testNode.parentNode === container ) {
return testNode;
}
}
// If no node was found, create it now
let node = document.createElement( tagname );
node.className = classname;
node.innerHTML = innerHTML;
container.appendChild( node );
return node;
}
/**
* Injects the given CSS styles into the DOM.
*
* @param {string} value
*/
export const createStyleSheet = ( value ) => {
let tag = document.createElement( 'style' );
tag.type = 'text/css';
if( value && value.length > 0 ) {
if( tag.styleSheet ) {
tag.styleSheet.cssText = value;
}
else {
tag.appendChild( document.createTextNode( value ) );
}
}
document.head.appendChild( tag );
return tag;
}
/**
* Returns a key:value hash of all query params.
*/
export const getQueryHash = () => {
let query = {};
location.search.replace( /[A-Z0-9]+?=([\w\.%-]*)/gi, a => {
query[ a.split( '=' ).shift() ] = a.split( '=' ).pop();
} );
// Basic deserialization
for( let i in query ) {
let value = query[ i ];
query[ i ] = deserialize( unescape( value ) );
}
// Do not accept new dependencies via query config to avoid
// the potential of malicious script injection
if( typeof query['dependencies'] !== 'undefined' ) delete query['dependencies'];
return query;
}
/**
* Returns the remaining height within the parent of the
* target element.
*
* remaining height = [ configured parent height ] - [ current parent height ]
*
* @param {HTMLElement} element
* @param {number} [height]
*/
export const getRemainingHeight = ( element, height = 0 ) => {
if( element ) {
let newHeight, oldHeight = element.style.height;
// Change the .stretch element height to 0 in order find the height of all
// the other elements
element.style.height = '0px';
// In Overview mode, the parent (.slide) height is set of 700px.
// Restore it temporarily to its natural height.
element.parentNode.style.height = 'auto';
newHeight = height - element.parentNode.offsetHeight;
// Restore the old height, just in case
element.style.height = oldHeight + 'px';
// Clear the parent (.slide) height. .removeProperty works in IE9+
element.parentNode.style.removeProperty('height');
return newHeight;
}
return height;
}
