Incrementing state value by one using React

Question

In React I am trying to make a button increment a value stored in state. However using the code below function my value is set undefined or NaN when using handleClick.

Answer 1

You can do it this way also where we do both increment and decrement operation with same function making it more modular and redable

class CounterApp extends React.Component{

    constructor(){
        super();
        //here count is initially assigned with 0
        this.state ={
        count:0
        }
    }
    
    //when we click Increment or Decrement +1 or -1 is passed to step and the value gets changed it gets updated to the view
    increment = (step) =>{
        this.setState({
            count:this.state.count + step
        })
    }
    render(){
        const { count } = this.state;//same as const count = this.state.count;

        return(
            

                

                    
{count}
                     this.increment(+1)}>Increment
                     this.increment(-1)}>Decrement
                
            
        )
    }
}