React setState

setState.js

/*
The setState() method does not immediately update the state of the component, 
it just puts the update in a queue to be processed later. 
React may batch multiple update requests together to make rendering more efficient.
Due to this, special precautions must be made when you try to update 
the state based on the component's previous state.
*/  

state = { count: 1 };
  componentDidMount() {
    // this.setState({ count: this.state.count + 1 });
    // this.setState({ count: this.state.count + 1 });
    // this.setState({ count: this.state.count + 1 });
    // count = 1;
    /*
    Object.assign(  
      {},
      { count: this.state.count + 1 },
      { count: this.state.count + 1 },
      { count: this.state.count + 1 },
    )
    */
    
    
    this.setState(prevState => ({ count: prevState.count + 1 }));
    this.setState(prevState => ({ count: prevState.count + 1 }));
    this.setState(prevState => ({ count: prevState.count + 1 }));
    //count = 4
  }