fix for #1

Author: thecodejack

src/components/Switch.svelte

@@ -54,7 +54,7 @@
  //event handlers
 
  function onDragStart(clientX) {
- inputRef.focus();
+ inputRef && inputRef.focus && inputRef.focus();
  state.startX = clientX;
  state.hasOutline = true;
  state.dragStartingTime = Date.now();