[reactjs] expected assignment or function call: no-unused-expressions ReactJS

In my case, I got the error on the setState line:

increment(){
  this.setState(state => {
    count: state.count + 1
  });
}

I changed it to this, now it works

increment(){
  this.setState(state => {
    const count = state.count + 1

    return {
      count
    };
  });
}