ReactJs_component_api

import React from 'react';

import PropTypes from 'prop-types';

import ReactDOM from 'react-dom';

class App extends React.Component {

  constructor(){

    super();

    this.state = {

      data: []

    }

    this.setStateHandler = this.setStateHandler.bind(this);

  };

  

  setStateHandler(){

    var item = "setState..."

    var myArray = this.state.data.slice();

    myArray.push(item);

    this.setState({data: myArray})

  };

   render() {

      return (

         <div id = "app">

           <button onClick = {this.setStateHandler}>SET STATE</button>

           <h4>State Array : {this.state.data}</h4>

            </div>

      );

   }

}

export default App;