React with tailwind

I want to ask

• What is good approch to get the number of unchecked todo? Currently I use useEffect and detecting if the delete button is clicked to change the remaining todo number. But the code seems a little ugly.
• How to filter child component by child's state, like if I click completed button, only show the child if its checked state is true. Currently I only hidden the unchecked children

I have not complete the dragging function yet. Any feedback is welcome