tmaiaroto/telepathic-black-panther

module.exports = {
    first: function() {
        return $ki(this[0]);
    },
    last: function() {
        return $ki(this[this.length - 1]);
    },
    outerHeight: function() {
        this.each(function(b) {
            b.outerHeight = b.offsetHeight;
            var style = getComputedStyle(b);
            b.outerHeight += parseInt(style.marginTop) + parseInt(style.marginBottom);
        });
        return this.length > 1 ? this : this[0].outerHeight;
    },
    outerWidth: function() {
        this.each(function(b) {
            b.outerWidth = b.offsetWidth;
            var style = getComputedStyle(b);
            b.outerWidth += parseInt(style.marginLeft) + parseInt(style.marginRight);
        });
        return this.length > 1 ? this : this[0].outerWidth;
    },
    html: function(a) {
        return a === []._ ? this[0].innerHTML : this.each(function(b) {
            b.innerHTML = a;
        });
    },
    offset: function() {
        this.each(function(b) {
            var rect = b.getBoundingClientRect();
            b.offset = {
              top: rect.top + document.body.scrollTop,
              left: rect.left + document.body.scrollLeft
            };
        });
        return this.length > 1 ? this : this[0].offset;
    },
    hasClass: function(a) {
        return this[0].classList.contains(a);
    },
    /**
     * Determines if an element falls within the browser's viewport.
     * 
     * @param  {number}  x How much of the element must be visible along the x axis as a percentage (0, 0.5, 1, etc.)
     * @param  {number}  y How much of the element must be visible along the y axis as a percentage (0, 0.5, 1, etc.)
     * @return {boolean}   Whether or not enough of the element is visible on the screen to count
    */
    isOnScreen: function(x, y) {
        if(x === null || typeof x === 'undefined') { x = 1; }
        if(y === null || typeof y === 'undefined') { y = 1; }
        
        var viewport = {};
        viewport.left = (window.pageXOffset !== undefined) ? window.pageXOffset : (document.documentElement || document.body.parentNode || document.body).scrollLeft;
        viewport.top = (window.pageYOffset !== undefined) ? window.pageYOffset : (document.documentElement || document.body.parentNode || document.body).scrollTop;

        viewport.right = viewport.left + window.innerWidth;
        viewport.bottom = viewport.top + window.innerHeight;
        
        var height = this.outerHeight();
        var width = this.outerWidth();
     
        if(!width || !height){
            return false;
        }
        
        var bounds = this.offset();
        bounds.right = bounds.left + width;
        bounds.bottom = bounds.top + height;
        
        var visible = (!(viewport.right < bounds.left || viewport.left > bounds.right || viewport.bottom < bounds.top || viewport.top > bounds.bottom));
        
        if(!visible){
            return false;   
        }
        
        var deltas = {
            top : Math.min( 1, ( bounds.bottom - viewport.top ) / height),
            bottom : Math.min(1, ( viewport.bottom - bounds.top ) / height),
            left : Math.min(1, ( bounds.right - viewport.left ) / width),
            right : Math.min(1, ( viewport.right - bounds.left ) / width)
        };
        
        return (deltas.left * deltas.right) >= x && (deltas.top * deltas.bottom) >= y;
    }
};