imagesloaded.js

/*!
 * imagesLoaded v5.0.0
 * JavaScript is all like "You images are done yet or what?"
 * MIT License
 */

( function( window, factory ) {
  // universal module definition
  if ( typeof module == 'object' && module.exports ) {
    // CommonJS
    module.exports = factory( window, require('ev-emitter') );
  } else {
    // browser global
    window.imagesLoaded = factory( window, window.EvEmitter );
  }

} )( typeof window !== 'undefined' ? window : this,
    function factory( window, EvEmitter ) {

let $ = window.jQuery;
let console = window.console;

// -------------------------- helpers -------------------------- //

// turn element or nodeList into an array
function makeArray( obj ) {
  // use object if already an array
  if ( Array.isArray( obj ) ) return obj;

  let isArrayLike = typeof obj == 'object' && typeof obj.length == 'number';
  // convert nodeList to array
  if ( isArrayLike ) return [ ...obj ];

  // array of single index
  return [ obj ];
}

// -------------------------- imagesLoaded -------------------------- //

/**
 * @param {[Array, Element, NodeList, String]} elem
 * @param {[Object, Function]} options - if function, use as callback
 * @param {Function} onAlways - callback function
 * @returns {ImagesLoaded}
 */
function ImagesLoaded( elem, options, onAlways ) {
  // coerce ImagesLoaded() without new, to be new ImagesLoaded()
  if ( !( this instanceof ImagesLoaded ) ) {
    return new ImagesLoaded( elem, options, onAlways );
  }
  // use elem as selector string
  let queryElem = elem;
  if ( typeof elem == 'string' ) {
    queryElem = document.querySelectorAll( elem );
  }
  // bail if bad element
  if ( !queryElem ) {
    console.error(`Bad element for imagesLoaded ${queryElem || elem}`);
    return;
  }

  this.elements = makeArray( queryElem );
  this.options = {};
  // shift arguments if no options set
  if ( typeof options == 'function' ) {
    onAlways = options;
  } else {
    Object.assign( this.options, options );
  }

  if ( onAlways ) this.on( 'always', onAlways );

  this.getImages();
  // add jQuery Deferred object
  if ( $ ) this.jqDeferred = new $.Deferred();

  // HACK check async to allow time to bind listeners
  setTimeout( this.check.bind( this ) );
}

ImagesLoaded.prototype = Object.create( EvEmitter.prototype );

ImagesLoaded.prototype.getImages = function() {
  this.images = [];

  // filter & find items if we have an item selector
  this.elements.forEach( this.addElementImages, this );
};

const elementNodeTypes = [ 1, 9, 11 ];

/**
 * @param {Node} elem
 */
ImagesLoaded.prototype.addElementImages = function( elem ) {
  // filter siblings
  if ( elem.nodeName === 'IMG' ) {
    this.addImage( elem );
  }
  // get background image on element
  if ( this.options.background === true ) {
    this.addElementBackgroundImages( elem );
  }

  // find children
  // no non-element nodes, #143
  let { nodeType } = elem;
  if ( !nodeType || !elementNodeTypes.includes( nodeType ) ) return;

  let childImgs = elem.querySelectorAll('img');
  // concat childElems to filterFound array
  for ( let img of childImgs ) {
    this.addImage( img );
  }

  // get child background images
  if ( typeof this.options.background == 'string' ) {
    let children = elem.querySelectorAll( this.options.background );
    for ( let child of children ) {
      this.addElementBackgroundImages( child );
    }
  }
};

const reURL = /url\((['"])?(.*?)\1\)/gi;

ImagesLoaded.prototype.addElementBackgroundImages = function( elem ) {
  let style = getComputedStyle( elem );
  // Firefox returns null if in a hidden iframe https://bugzil.la/548397
  if ( !style ) return;

  // get url inside url("...")
  let matches = reURL.exec( style.backgroundImage );
  while ( matches !== null ) {
    let url = matches && matches[2];
    if ( url ) {
      this.addBackground( url, elem );
    }
    matches = reURL.exec( style.backgroundImage );
  }
};

/**
 * @param {Image} img
 */
ImagesLoaded.prototype.addImage = function( img ) {
  let loadingImage = new LoadingImage( img );
  this.images.push( loadingImage );
};

ImagesLoaded.prototype.addBackground = function( url, elem ) {
  let background = new Background( url, elem );
  this.images.push( background );
};

ImagesLoaded.prototype.check = function() {
  this.progressedCount = 0;
  this.hasAnyBroken = false;
  // complete if no images
  if ( !this.images.length ) {
    this.complete();
    return;
  }

  /* eslint-disable-next-line func-style */
  let onProgress = ( image, elem, message ) => {
    // HACK - Chrome triggers event before object properties have changed. #83
    setTimeout( () => {
      this.progress( image, elem, message );
    } );
  };

  this.images.forEach( function( loadingImage ) {
    loadingImage.once( 'progress', onProgress );
    loadingImage.check();
  } );
};

ImagesLoaded.prototype.progress = function( image, elem, message ) {
  this.progressedCount++;
  this.hasAnyBroken = this.hasAnyBroken || !image.isLoaded;
  // progress event
  this.emitEvent( 'progress', [ this, image, elem ] );
  if ( this.jqDeferred && this.jqDeferred.notify ) {
    this.jqDeferred.notify( this, image );
  }
  // check if completed
  if ( this.progressedCount === this.images.length ) {
    this.complete();
  }

  if ( this.options.debug && console ) {
    console.log( `progress: ${message}`, image, elem );
  }
};

ImagesLoaded.prototype.complete = function() {
  let eventName = this.hasAnyBroken ? 'fail' : 'done';
  this.isComplete = true;
  this.emitEvent( eventName, [ this ] );
  this.emitEvent( 'always', [ this ] );
  if ( this.jqDeferred ) {
    let jqMethod = this.hasAnyBroken ? 'reject' : 'resolve';
    this.jqDeferred[ jqMethod ]( this );
  }
};

// --------------------------  -------------------------- //

function LoadingImage( img ) {
  this.img = img;
}

LoadingImage.prototype = Object.create( EvEmitter.prototype );

LoadingImage.prototype.check = function() {
  // If complete is true and browser supports natural sizes,
  // try to check for image status manually.
  let isComplete = this.getIsImageComplete();
  if ( isComplete ) {
    // report based on naturalWidth
    this.confirm( this.img.naturalWidth !== 0, 'naturalWidth' );
    return;
  }

  // If none of the checks above matched, simulate loading on detached element.
  this.proxyImage = new Image();
  // add crossOrigin attribute. #204
  if ( this.img.crossOrigin ) {
    this.proxyImage.crossOrigin = this.img.crossOrigin;
  }
  this.proxyImage.addEventListener( 'load', this );
  this.proxyImage.addEventListener( 'error', this );
  // bind to image as well for Firefox. #191
  this.img.addEventListener( 'load', this );
  this.img.addEventListener( 'error', this );
  this.proxyImage.src = this.img.currentSrc || this.img.src;
};

LoadingImage.prototype.getIsImageComplete = function() {
  // check for non-zero, non-undefined naturalWidth
  // fixes Safari+InfiniteScroll+Masonry bug infinite-scroll#671
  return this.img.complete && this.img.naturalWidth;
};

LoadingImage.prototype.confirm = function( isLoaded, message ) {
  this.isLoaded = isLoaded;
  let { parentNode } = this.img;
  // emit progress with parent <picture> or self <img>
  let elem = parentNode.nodeName === 'PICTURE' ? parentNode : this.img;
  this.emitEvent( 'progress', [ this, elem, message ] );
};

// ----- events ----- //

// trigger specified handler for event type
LoadingImage.prototype.handleEvent = function( event ) {
  let method = 'on' + event.type;
  if ( this[ method ] ) {
    this[ method ]( event );
  }
};

LoadingImage.prototype.onload = function() {
  this.confirm( true, 'onload' );
  this.unbindEvents();
};

LoadingImage.prototype.onerror = function() {
  this.confirm( false, 'onerror' );
  this.unbindEvents();
};

LoadingImage.prototype.unbindEvents = function() {
  this.proxyImage.removeEventListener( 'load', this );
  this.proxyImage.removeEventListener( 'error', this );
  this.img.removeEventListener( 'load', this );
  this.img.removeEventListener( 'error', this );
};

// -------------------------- Background -------------------------- //

function Background( url, element ) {
  this.url = url;
  this.element = element;
  this.img = new Image();
}

// inherit LoadingImage prototype
Background.prototype = Object.create( LoadingImage.prototype );

Background.prototype.check = function() {
  this.img.addEventListener( 'load', this );
  this.img.addEventListener( 'error', this );
  this.img.src = this.url;
  // check if image is already complete
  let isComplete = this.getIsImageComplete();
  if ( isComplete ) {
    this.confirm( this.img.naturalWidth !== 0, 'naturalWidth' );
    this.unbindEvents();
  }
};

Background.prototype.unbindEvents = function() {
  this.img.removeEventListener( 'load', this );
  this.img.removeEventListener( 'error', this );
};

Background.prototype.confirm = function( isLoaded, message ) {
  this.isLoaded = isLoaded;
  this.emitEvent( 'progress', [ this, this.element, message ] );
};

// -------------------------- jQuery -------------------------- //

ImagesLoaded.makeJQueryPlugin = function( jQuery ) {
  jQuery = jQuery || window.jQuery;
  if ( !jQuery ) return;

  // set local variable
  $ = jQuery;
  // $().imagesLoaded()
  $.fn.imagesLoaded = function( options, onAlways ) {
    let instance = new ImagesLoaded( this, options, onAlways );
    return instance.jqDeferred.promise( $( this ) );
  };
};
// try making plugin
ImagesLoaded.makeJQueryPlugin();

// --------------------------  -------------------------- //

return ImagesLoaded;

} );