spaces-demo.js

      const originalMouseX = resizeType === ResizeType.Left ? e.pageX + space.adjustedSize : e.pageX - space.adjustedSize;
      const originalMouseY = resizeType === ResizeType.Top ? e.pageY + space.adjustedSize : e.pageY - space.adjustedSize;
      const minimumAdjust = (props.minimumSize === undefined ? 20 : props.minimumSize) - size + space.adjustedSize;
      const maximumAdjust = props.maximumSize ? (props.maximumSize - size + space.adjustedSize) : undefined;
      let lastX = 0;
      let lastY = 0;
      let moved = false;

      const mouseResize = (x, y, startX = originalMouseX, startY = originalMouseY) => onResize(startX, startY, x, y, minimumAdjust, maximumAdjust);
      const throttledMouseResize = throttle<typeof mouseResize>(mouseResize, RESIZE_THROTTLE);
      const withPreventDefault = (e: MouseEvent) => { 
        moved = true; 
        lastX = e.pageX;
        lastY = e.pageY;
        e.preventDefault(); 
        e.stopImmediatePropagation(); 
        throttledMouseResize(lastX, lastY); 
      };
      const removeListener = () => {
        if (moved) {
          //  Not sure about the right math here, but need to get the final bounds to pass correct values to onResize
          // const currentRect = divElementRef.current.getBoundingClientRect();
          // const startX = ?
          // const startY = ?
          mouseResize(lastX, lastY, startX, startY);
        }
        window.removeEventListener('mousemove', withPreventDefault);
        window.removeEventListener('mouseup', removeListener);
        onResizeEnd(currentRect); //  Pass rect (or more relevant value(s)) and skip running getBoundingClientRect() there
      };
      window.addEventListener('mousemove', withPreventDefault);
      window.addEventListener('mouseup', removeListener);
      e.preventDefault();
      e.stopPropagation();
      props.onResizeStart && props.onResizeStart();