hero.js

"use strict";
var raf = (typeof window !== 'undefined' && window.requestAnimationFrame) || setTimeout;
var nextFrame = function (fn) { raf(function () { raf(fn); }); };
function setNextFrame(obj, prop, val) {
    nextFrame(function () { obj[prop] = val; });
}
function getTextNodeRect(textNode) {
    var rect;
    if (document.createRange) {
        var range = document.createRange();
        range.selectNodeContents(textNode);
        if (range.getBoundingClientRect) {
            rect = range.getBoundingClientRect();
        }
    }
    return rect;
}
function calcTransformOrigin(isTextNode, textRect, boundingRect) {
    if (isTextNode) {
        if (textRect) {
            //calculate pixels to center of text from left edge of bounding box
            var relativeCenterX = textRect.left + textRect.width / 2 - boundingRect.left;
            var relativeCenterY = textRect.top + textRect.height / 2 - boundingRect.top;
            return relativeCenterX + 'px ' + relativeCenterY + 'px';
        }
    }
    return '0 0'; //top left
}
function getTextDx(oldTextRect, newTextRect) {
    if (oldTextRect && newTextRect) {
        return ((oldTextRect.left + oldTextRect.width / 2) - (newTextRect.left + newTextRect.width / 2));
    }
    return 0;
}
function getTextDy(oldTextRect, newTextRect) {
    if (oldTextRect && newTextRect) {
        return ((oldTextRect.top + oldTextRect.height / 2) - (newTextRect.top + newTextRect.height / 2));
    }
    return 0;
}
function isTextElement(elm) {
    return elm.childNodes.length === 1 && elm.childNodes[0].nodeType === 3;
}
var removed, created;
function pre() {
    removed = {};
    created = [];
}
function create(oldVnode, vnode) {
    var hero = vnode.data.hero;
    if (hero && hero.id) {
        created.push(hero.id);
        created.push(vnode);
    }
}
function destroy(vnode) {
    var hero = vnode.data.hero;
    if (hero && hero.id) {
        var elm = vnode.elm;
        vnode.isTextNode = isTextElement(elm); //is this a text node?
        vnode.boundingRect = elm.getBoundingClientRect(); //save the bounding rectangle to a new property on the vnode
        vnode.textRect = vnode.isTextNode ? getTextNodeRect(elm.childNodes[0]) : null; //save bounding rect of inner text node
        var computedStyle = window.getComputedStyle(elm, void 0); //get current styles (includes inherited properties)
        vnode.savedStyle = JSON.parse(JSON.stringify(computedStyle)); //save a copy of computed style values
        removed[hero.id] = vnode;
    }
}
function post() {
    var i, id, newElm, oldVnode, oldElm, hRatio, wRatio, oldRect, newRect, dx, dy, origTransform, origTransition, newStyle, oldStyle, newComputedStyle, isTextNode, newTextRect, oldTextRect;
    for (i = 0; i < created.length; i += 2) {
        id = created[i];
        newElm = created[i + 1].elm;
        oldVnode = removed[id];
        if (oldVnode) {
            isTextNode = oldVnode.isTextNode && isTextElement(newElm); //Are old & new both text?
            newStyle = newElm.style;
            newComputedStyle = window.getComputedStyle(newElm, void 0); //get full computed style for new element
            oldElm = oldVnode.elm;
            oldStyle = oldElm.style;
            //Overall element bounding boxes
            newRect = newElm.getBoundingClientRect();
            oldRect = oldVnode.boundingRect; //previously saved bounding rect
            //Text node bounding boxes & distances
            if (isTextNode) {
                newTextRect = getTextNodeRect(newElm.childNodes[0]);
                oldTextRect = oldVnode.textRect;
                dx = getTextDx(oldTextRect, newTextRect);
                dy = getTextDy(oldTextRect, newTextRect);
            }
            else {
                //Calculate distances between old & new positions
                dx = oldRect.left - newRect.left;
                dy = oldRect.top - newRect.top;
            }
            hRatio = newRect.height / (Math.max(oldRect.height, 1));
            wRatio = isTextNode ? hRatio : newRect.width / (Math.max(oldRect.width, 1)); //text scales based on hRatio
            // Animate new element
            origTransform = newStyle.transform;
            origTransition = newStyle.transition;
            if (newComputedStyle.display === 'inline') //inline elements cannot be transformed
                newStyle.display = 'inline-block'; //this does not appear to have any negative side effects
            newStyle.transition = origTransition + 'transform 0s';
            newStyle.transformOrigin = calcTransformOrigin(isTextNode, newTextRect, newRect);
            newStyle.opacity = '0';
            newStyle.transform = origTransform + 'translate(' + dx + 'px, ' + dy + 'px) ' +
                'scale(' + 1 / wRatio + ', ' + 1 / hRatio + ')';
            setNextFrame(newStyle, 'transition', origTransition);
            setNextFrame(newStyle, 'transform', origTransform);
            setNextFrame(newStyle, 'opacity', '1');
            // Animate old element
            for (var key in oldVnode.savedStyle) { //re-apply saved inherited properties
                if (parseInt(key) != key) {
                    var ms = key.substring(0, 2) === 'ms';
                    var moz = key.substring(0, 3) === 'moz';
                    var webkit = key.substring(0, 6) === 'webkit';
                    if (!ms && !moz && !webkit) //ignore prefixed style properties
                        oldStyle[key] = oldVnode.savedStyle[key];
                }
            }
            oldStyle.position = 'absolute';
            oldStyle.top = oldRect.top + 'px'; //start at existing position
            oldStyle.left = oldRect.left + 'px';
            oldStyle.width = oldRect.width + 'px'; //Needed for elements who were sized relative to their parents
            oldStyle.height = oldRect.height + 'px'; //Needed for elements who were sized relative to their parents
            oldStyle.margin = '0'; //Margin on hero element leads to incorrect positioning
            oldStyle.transformOrigin = calcTransformOrigin(isTextNode, oldTextRect, oldRect);
            oldStyle.transform = '';
            oldStyle.opacity = '1';
            document.body.appendChild(oldElm);
            setNextFrame(oldStyle, 'transform', 'translate(' + -dx + 'px, ' + -dy + 'px) scale(' + wRatio + ', ' + hRatio + ')'); //scale must be on far right for translate to be correct
            setNextFrame(oldStyle, 'opacity', '0');
            oldElm.addEventListener('transitionend', function (ev) {
                if (ev.propertyName === 'transform')
                    document.body.removeChild(ev.target);
            });
        }
    }
    removed = created = undefined;
}
var heroModule = { pre: pre, create: create, destroy: destroy, post: post };