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

Try this out

class QuestionList extends React.component {

    constructor(props){
        super(props)
        this.state = {
            value : 0
        }
    }

    handleClick(){
        this.setState({
            value : this.state.value + 1
        })
    }

   render(){
        return(  {this.state.value}  )
   }
}

Note that when you set a state, it triggers the render function, which will reflect the current state. Try it out in the browser!