スプリング開閉ドラッグトグル

<div class="d08-15-09-toggle" id="d08-15-09-toggle">
          <div class="d08-15-09-knob" id="d08-15-09-knob"></div>
        </div>

.d08-15-09{width:100%;display:flex;align-items:center;justify-content:center}
        .d08-15-09-toggle{position:relative;width:76px;height:34px;border-radius:99px;background:#dcdfe6;transition:background .25s}
        .d08-15-09-toggle.is-on{background:linear-gradient(90deg,#6a5cff,#8b5cf6)}
        .d08-15-09-knob{position:absolute;top:4px;left:4px;width:26px;height:26px;border-radius:50%;background:#fff;box-shadow:0 2px 6px rgba(0,0,0,.22);cursor:grab;touch-action:none}
        .d08-15-09-knob.is-drag{cursor:grabbing}

(function(){
        var root=document.getElementById('item-08-15-09');if(!root)return;
        var toggle=root.querySelector('#d08-15-09-toggle'),knob=root.querySelector('#d08-15-09-knob');
        if(!toggle||!knob)return;
        var MAXX=42,dragging=false,startX=0,startTx=0,curTx=0,raf=null;
        function apply(x){knob.style.transform='translateX('+x+'px)';}
        knob.addEventListener('pointerdown',function(e){
          dragging=true;knob.classList.add('is-drag');
          if(raf)cancelAnimationFrame(raf);
          startX=e.clientX;startTx=curTx;
          try{knob.setPointerCapture(e.pointerId);}catch(err){}
        });
        knob.addEventListener('pointermove',function(e){
          if(!dragging)return;
          var dx=e.clientX-startX;
          curTx=Math.max(0,Math.min(MAXX,startTx+dx));
          apply(curTx);
        });
        function end(){
          if(!dragging)return;
          dragging=false;knob.classList.remove('is-drag');
          var target=curTx>MAXX/2?MAXX:0;
          toggle.classList.toggle('is-on',target===MAXX);
          var x=curTx,v=0,stiff=.22,damp=.68;
          function step(){
            var f=(target-x)*stiff;v=(v+f)*damp;x+=v;curTx=x;apply(x);
            if(Math.abs(target-x)>.5||Math.abs(v)>.5){raf=requestAnimationFrame(step);}
            else{curTx=target;apply(target);}
          }
          raf=requestAnimationFrame(step);
        }
        knob.addEventListener('pointerup',end);
        knob.addEventListener('pointercancel',end);
      })();