Cannot get parameters in function

<script>
    let step = 10, //
        index = 0, //
        flag = -1, //
        dis = 0, //
        width = 400, //
        num = 5; //
    const pics = ["../one.jpg", "../two.jpg", "../three.jpg", "../four.jpg", "../five.jpg"];
    let wrapper = document.querySelector(".wrapper");
    let menu = document.querySelector(".menu");
    //
    pics.forEach(val => {
        let img = document.createElement("img");
        let smallImg = document.createElement("img");
        img.src = val;
        smallImg.src = val;
        wrapper.appendChild(img);
        menu.appendChild(smallImg);
    });

    //
    function addPic() {
        pics.forEach(val => {
            let img = document.createElement("img");
            img.src = val;
            wrapper.appendChild(img);
        });
    }
    //style
    function getStyle(ele, cssname) {
        if (window.getComputedStyle) {
            return window.getComputedStyle(ele)[cssname];
        } else {
            return ele.currentStyle[cssname];
        }
    }
    //
    function pace() {
        let curPos = parseInt(getStyle(wrapper, "left"));
        console.log("pace");
        console.log(to);
        console.log(curPos);
        wrapper.style.left = curPos + flag * step + "px";
        dis += flag * step;
        //
        if (Math.abs(to - dis) < step) {
            wrapper.style.left = to + "px";
            dis = to;
            indexPP;
            clearInterval(pacer);
            // setTimeout(() => {
            //     timer = setInterval(pace, 100);
            // }, 2000);
        } else {
            wrapper.style.left = curPos + flag * step + "px";
            dis += flag * step;
        }
    }
    //
    function move(direction) {
        let to = -width * index; // 
        // -1-left 1-right
        flag = direction === 1 ? 1 : -1;
        console.log(to);
        console.log(dis);
        pacer = setInterval(pace, 100);
    }

    //
    function auto() {
        addPic();
        indexPP;
        move(flag);
    }
    auto();
</script>

browsers keep prompting
Uncaught ReferenceError: to is not defined at pace

but isn"t to defined in move ()?

I don"t know what"s wrong with it. Ask the bosses for advice.

let a = '123' function move(direction) { let to = 'xxx' // to == 'xxx' console.log(to) // xxx console.log(a) // 123 } function A(){ console.log(to) // undefined console.log(a) // 123 } console.log(to) // undefined console.log(a) // 123