/*!
 * Infinite Scroll v2.0.4
 * measure size of elements
 * MIT license
 */

( function( window, factory ) {
  if ( typeof module == 'object' && module.exports ) {
    // CommonJS
    module.exports = factory();
  } else {
    // browser global
    window.getSize = factory();
  }

} )( window, function factory() {

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

// get a number from a string, not a percentage
function getStyleSize( value ) {
  let num = parseFloat( value );
  // not a percent like '100%', and a number
  let isValid = value.indexOf('%') == -1 && !isNaN( num );
  return isValid && num;
}

// -------------------------- measurements -------------------------- //

let measurements = [
  'paddingLeft',
  'paddingRight',
  'paddingTop',
  'paddingBottom',
  'marginLeft',
  'marginRight',
  'marginTop',
  'marginBottom',
  'borderLeftWidth',
  'borderRightWidth',
  'borderTopWidth',
  'borderBottomWidth',
];

let measurementsLength = measurements.length;

function getZeroSize() {
  let size = {
    width: 0,
    height: 0,
    innerWidth: 0,
    innerHeight: 0,
    outerWidth: 0,
    outerHeight: 0,
  };
  measurements.forEach( ( measurement ) => {
    size[ measurement ] = 0;
  } );
  return size;
}

// -------------------------- getSize -------------------------- //

function getSize( elem ) {
  // use querySeletor if elem is string
  if ( typeof elem == 'string' ) elem = document.querySelector( elem );

  // do not proceed on non-objects
  let isElement = elem && typeof elem == 'object' && elem.nodeType;
  if ( !isElement ) return;

  let style = getComputedStyle( elem );

  // if hidden, everything is 0
  if ( style.display == 'none' ) return getZeroSize();

  let size = {};
  size.width = elem.offsetWidth;
  size.height = elem.offsetHeight;

  let isBorderBox = size.isBorderBox = style.boxSizing == 'border-box';

  // get all measurements
  measurements.forEach( ( measurement ) => {
    let value = style[ measurement ];
    let num = parseFloat( value );
    // any 'auto', 'medium' value will be 0
    size[ measurement ] = !isNaN( num ) ? num : 0;
  } );

  let paddingWidth = size.paddingLeft + size.paddingRight;
  let paddingHeight = size.paddingTop + size.paddingBottom;
  let marginWidth = size.marginLeft + size.marginRight;
  let marginHeight = size.marginTop + size.marginBottom;
  let borderWidth = size.borderLeftWidth + size.borderRightWidth;
  let borderHeight = size.borderTopWidth + size.borderBottomWidth;

  // overwrite width and height if we can get it from style
  let styleWidth = getStyleSize( style.width );
  if ( styleWidth !== false ) {
    size.width = styleWidth +
      // add padding and border unless it's already including it
      ( isBorderBox ? 0 : paddingWidth + borderWidth );
  }

  let styleHeight = getStyleSize( style.height );
  if ( styleHeight !== false ) {
    size.height = styleHeight +
      // add padding and border unless it's already including it
      ( isBorderBox ? 0 : paddingHeight + borderHeight );
  }

  size.innerWidth = size.width - ( paddingWidth + borderWidth );
  size.innerHeight = size.height - ( paddingHeight + borderHeight );

  size.outerWidth = size.width + marginWidth;
  size.outerHeight = size.height + marginHeight;

  return size;
}

return getSize;

} );