imagesloaded/imagesloaded.js

/*!
 * imagesLoaded v3.1.2
 * JavaScript is all like "You images are done yet or what?"
 * MIT License
 */

( function( window ) {

'use strict';

var $ = window.jQuery;
var console = window.console;
var hasConsole = typeof console !== 'undefined';

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

// extend objects
function extend( a, b ) {
  for ( var prop in b ) {
    a[ prop ] = b[ prop ];
  }
  return a;
}

var objToString = Object.prototype.toString;
function isArray( obj ) {
  return objToString.call( obj ) === '[object Array]';
}

// turn element or nodeList into an array
function makeArray( obj ) {
  var ary = [];
  if ( isArray( obj ) ) {
    // use object if already an array
    ary = obj;
  } else if ( typeof obj.length === 'number' ) {
    // convert nodeList to array
    for ( var i=0, len = obj.length; i < len; i++ ) {
      ary.push( obj[i] );
    }
  } else {
    // array of single index
    ary.push( obj );
  }
  return ary;
}

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

function defineImagesLoaded( EventEmitter, eventie ) {

  /**
   * @param {Array, Element, NodeList, String} elem
   * @param {Object or Function} options - if function, use as callback
   * @param {Function} onAlways - callback function
   */
  function ImagesLoaded( elem, options, onAlways ) {
    // coerce ImagesLoaded() without new, to be new ImagesLoaded()
    if ( !( this instanceof ImagesLoaded ) ) {
      return new ImagesLoaded( elem, options );
    }
    // use elem as selector string
    if ( typeof elem === 'string' ) {
      elem = document.querySelectorAll( elem );
    }

    this.elements = makeArray( elem );
    this.options = extend( {}, this.options );

    if ( typeof options === 'function' ) {
      onAlways = options;
    } else {
      extend( this.options, options );
    }

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

    this.getImages();

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

    // HACK check async to allow time to bind listeners
    var _this = this;
    setTimeout( function() {
      _this.check();
    });
  }

  ImagesLoaded.prototype = new EventEmitter();

  ImagesLoaded.prototype.options = {};

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

    // filter & find items if we have an item selector
    for ( var i=0, len = this.elements.length; i < len; i++ ) {
      var elem = this.elements[i];
      // filter siblings
      if ( elem.nodeName === 'IMG' ) {
        this.addImage( elem );
      }
      // find children
      var childElems = elem.querySelectorAll('img');
      // concat childElems to filterFound array
      for ( var j=0, jLen = childElems.length; j < jLen; j++ ) {
        var img = childElems[j];
        this.addImage( img );
      }
    }
  };

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

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

    function onConfirm( image, message ) {
      if ( _this.options.debug && hasConsole ) {
        console.log( 'confirm', image, message );
      }

      _this.progress( image );
      checkedCount++;
      if ( checkedCount === length ) {
        _this.complete();
      }
      return true; // bind once
    }

    for ( var i=0; i < length; i++ ) {
      var loadingImage = this.images[i];
      loadingImage.on( 'confirm', onConfirm );
      loadingImage.check();
    }
  };

  ImagesLoaded.prototype.progress = function( image ) {
    this.hasAnyBroken = this.hasAnyBroken || !image.isLoaded;
    // HACK - Chrome triggers event before object properties have changed. #83
    var _this = this;
    setTimeout( function() {
      _this.emit( 'progress', _this, image );
      if ( _this.jqDeferred && _this.jqDeferred.notify ) {
        _this.jqDeferred.notify( _this, image );
      }
    });
  };

  ImagesLoaded.prototype.complete = function() {
    var eventName = this.hasAnyBroken ? 'fail' : 'done';
    this.isComplete = true;
    var _this = this;
    // HACK - another setTimeout so that confirm happens after progress
    setTimeout( function() {
      _this.emit( eventName, _this );
      _this.emit( 'always', _this );
      if ( _this.jqDeferred ) {
        var jqMethod = _this.hasAnyBroken ? 'reject' : 'resolve';
        _this.jqDeferred[ jqMethod ]( _this );
      }
    });
  };

  // -------------------------- jquery -------------------------- //

  if ( $ ) {
    $.fn.imagesLoaded = function( options, callback ) {
      var instance = new ImagesLoaded( this, options, callback );
      return instance.jqDeferred.promise( $(this) );
    };
  }


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

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

  LoadingImage.prototype = new EventEmitter();

  LoadingImage.prototype.check = function() {
    // first check cached any previous images that have same src
    var resource = cache[ this.img.src ] || new Resource( this.img.src );
    if ( resource.isConfirmed ) {
      this.confirm( resource.isLoaded, 'cached was confirmed' );
      return;
    }

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

    // If none of the checks above matched, simulate loading on detached element.
    var _this = this;
    resource.on( 'confirm', function( resrc, message ) {
      _this.confirm( resrc.isLoaded, message );
      return true;
    });

    resource.check();
  };

  LoadingImage.prototype.confirm = function( isLoaded, message ) {
    this.isLoaded = isLoaded;
    this.emit( 'confirm', this, message );
  };

  // -------------------------- Resource -------------------------- //

  // Resource checks each src, only once
  // separate class from LoadingImage to prevent memory leaks. See #115

  var cache = {};

  function Resource( src ) {
    this.src = src;
    // add to cache
    cache[ src ] = this;
  }

  Resource.prototype = new EventEmitter();

  Resource.prototype.check = function() {
    // only trigger checking once
    if ( this.isChecked ) {
      return;
    }
    // simulate loading on detached element
    var proxyImage = new Image();
    eventie.bind( proxyImage, 'load', this );
    eventie.bind( proxyImage, 'error', this );
    proxyImage.src = this.src;
    // set flag
    this.isChecked = true;
  };

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

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

  Resource.prototype.onload = function( event ) {
    this.confirm( true, 'onload' );
    this.unbindProxyEvents( event );
  };

  Resource.prototype.onerror = function( event ) {
    this.confirm( false, 'onerror' );
    this.unbindProxyEvents( event );
  };

  // ----- confirm ----- //

  Resource.prototype.confirm = function( isLoaded, message ) {
    this.isConfirmed = true;
    this.isLoaded = isLoaded;
    this.emit( 'confirm', this, message );
  };

  Resource.prototype.unbindProxyEvents = function( event ) {
    eventie.unbind( event.target, 'load', this );
    eventie.unbind( event.target, 'error', this );
  };

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

  return ImagesLoaded;
}

// -------------------------- transport -------------------------- //

if ( typeof define === 'function' && define.amd ) {
  // AMD
  define( [
      'eventEmitter/EventEmitter',
      'eventie/eventie'
    ],
    defineImagesLoaded );
} else {
  // browser global
  window.imagesLoaded = defineImagesLoaded(
    window.EventEmitter,
    window.eventie
  );
}

})( window );