jQuery 원페이지 스크립트

<script src="https://code.jquery.com/jquery-2.2.4.min.js"></script>
<div class="header">
    <ul>
        <li class="on" class="a"><a href="#">NAV01</a></li>
        <li><a href="#">NAV02</a></li>
        <li><a href="#">NAV03</a></li>
        <li><a href="#">NAV04</a></li>
    </ul>
</div>
<div class="content">
    <div class="cnt01"><p>CONTENT01</p></div>
    <div class="cnt02"><p>CONTENT02</p></div>
    <div class="cnt03"><p>CONTENT03</p></div>
    <div class="cnt04"><p>CONTENT04</p></div>
</div>
<style>
*{margin:0;padding:0}
html, body{overflow-y:hidden}
ul, ol{list-style:none}
.header{position:fixed;z-index:10;top:0;width:100%}
.header ul:after{content:"";display:block;clear:both}
.header ul li{float:left;border-left:1px solid rgba(255, 255, 255, 0);box-sizing:border-box;width:25%}
.header ul li:first-child{border-left:none}
.header ul li a{display:block;height:60px;text-align:center;line-height:60px;font-size:20px;text-decoration:none;background-color:#000;color:#fff}
.header ul li.on a{background-color:#fff;color:#000}
.content{}
.content div{position:relative}
.content div p{position:absolute;top:50%;margin-top:-40px;text-align:center;width:100%;font-size:80px;font-weight:bold;color:#fff}
.content .cnt01{background-color:#cc6666}
.content .cnt02{background-color:#9966cc}
.content .cnt03{background-color:#6699cc}
.content .cnt04{background-color:#66cc99}
</style>
<script>
let scroll = function(){
   
    let $nav = null,
        $cnt = null,
        moveCnt = null,
        moveIndex = 0,
        moveCntTop = 0,
        winH = 0,
        time = false; // 새로 만든 변수

    $(document).ready(function(){
        init();
        initEvent();
    });
   
    let init = function(){
        $cnt = $(".content");
        $nav = $(".menu a");
    };
   
    let initEvent = function(){
        $("html ,body").scrollTop(0);
        winResize();
        $(window).resize(function(){
            winResize();
        });
        $nav.on("click", function(){
            moveIndex = $(this).parent("li").index();
            moving(moveIndex);
            return false;
        });
        $cnt.on("mousewheel", function(e){
            if(time === false){ // time 변수가 펄스일때만 휠 이벤트 실행
              wheel(e);
            }
        });
    };
       
    let winResize = function(){
        winH = $(window).height();
        $cnt.children("div").height(winH);
        $("html ,body").scrollTop(moveIndex.scrollTop);
    };
   
    let wheel = function(e){
        if(e.originalEvent.wheelDelta < 0){
            if(moveIndex < 2){
                moveIndex += 1;
                moving(moveIndex);
            };
        }else{
            if(moveIndex > 0){
                moveIndex -= 1;
                moving(moveIndex);
            };
        };
    };
   
    let moving = function(index){
        time = true // 휠 이벤트가 실행 동시에 true로 변경
        moveCnt = $cnt.children("div").eq(index);
        moveCntTop = moveCnt.offset().top;
        $("html ,body").stop().animate({
            scrollTop: moveCntTop
        }, 1000, function(){
          time = false; // 휠 이벤트가 끝나면 false로 변경
        });
        $nav.parent(".menu li").eq(index).addClass("on").siblings().removeClass("on");
    };
   
};

scroll();

</script>