this.setState() in callback of this.setState()

Question

Can I explicitly call this.setState() in the definition of the callback passed to this.setState()?

this.setState(
 {
   openA:true 
 }, 
 () => {
   this.setState({
     openB: false
   })
 } 
)

Answer 1

This can be done, and this will result in 2 re-renders instead of 1. Usually there is no need to do this.

If setState are independent, it can be:

this.setState({ openA:true });
this.setState({ openB:false });

If updated states depend on each other, updater function should be used:

this.setState({ openA:true });
this.setState(state => ({ openB: !state.openA }));

Answer 2

Yes. It will run it after the first setState is complete.