elevator.min.js

var Elevator=function(options){"use strict";var body=null;var animation=null;var duration=null;var customDuration=false;var startTime=null;var startPosition=null;var endPosition=0;var targetElement=null;var verticalPadding=null;var elevating=false;var startCallback;var mainAudio;var endAudio;var endCallback;var that=this;function easeInOutQuad(t,b,c,d){t/=d/2;if(t<1)return c/2*t*t+b;t--;return-c/2*(t*(t-2)-1)+b}function extendParameters(options,defaults){for(var option in defaults){var t=options[option]===undefined&&typeof option!=="function";if(t){options[option]=defaults[option]}}return options}function getVerticalOffset(element){var verticalOffset=0;while(element){verticalOffset+=element.offsetTop||0;element=element.offsetParent}if(verticalPadding){verticalOffset=verticalOffset-verticalPadding}return verticalOffset}function animateLoop(time){if(!startTime){startTime=time}var timeSoFar=time-startTime;var easedPosition=easeInOutQuad(timeSoFar,startPosition,endPosition-startPosition,duration);window.scrollTo(0,easedPosition);if(timeSoFar<duration){animation=requestAnimationFrame(animateLoop)}else{animationFinished()}}this.elevate=function(){if(elevating){return}elevating=true;startPosition=document.documentElement.scrollTop||body.scrollTop;updateEndPosition();if(!customDuration){duration=Math.abs(endPosition-startPosition)*1.5}requestAnimationFrame(animateLoop);if(mainAudio){mainAudio.play()}if(startCallback){startCallback()}};function browserMeetsRequirements(){return window.requestAnimationFrame&&window.Audio&&window.addEventListener}function resetPositions(){startTime=null;startPosition=null;elevating=false}function updateEndPosition(){if(targetElement){endPosition=getVerticalOffset(targetElement)}}function animationFinished(){resetPositions();if(mainAudio){mainAudio.pause();mainAudio.currentTime=0}if(endAudio){endAudio.play()}if(endCallback){endCallback()}}function onWindowBlur(){if(elevating){cancelAnimationFrame(animation);resetPositions();if(mainAudio){mainAudio.pause();mainAudio.currentTime=0}updateEndPosition();window.scrollTo(0,endPosition)}}function bindElevateToElement(element){if(element.addEventListener){element.addEventListener("click",that.elevate,false)}else{element.attachEvent("onclick",function(){updateEndPosition();document.documentElement.scrollTop=endPosition;document.body.scrollTop=endPosition;window.scroll(0,endPosition)})}}function init(_options){body=document.body;var defaults={duration:undefined,mainAudio:false,endAudio:false,preloadAudio:true,loopAudio:true,startCallback:null,endCallback:null};_options=extendParameters(_options,defaults);if(_options.element){bindElevateToElement(_options.element)}if(!browserMeetsRequirements()){return}if(_options.duration){customDuration=true;duration=_options.duration}if(_options.targetElement){targetElement=_options.targetElement}if(_options.verticalPadding){verticalPadding=_options.verticalPadding}window.addEventListener("blur",onWindowBlur,false);if(_options.mainAudio){mainAudio=new Audio(_options.mainAudio);mainAudio.setAttribute("preload",_options.preloadAudio);mainAudio.setAttribute("loop",_options.loopAudio)}if(_options.endAudio){endAudio=new Audio(_options.endAudio);endAudio.setAttribute("preload","true")}if(_options.endCallback){endCallback=_options.endCallback}if(_options.startCallback){startCallback=_options.startCallback}}init(options)};module.exports=Elevator;