Hello everyone!
I added routers to my project and kept working and I don't know exactly what I did that caused the terminal to stop identifying the functions as defined... But probably that's because of the syntax or the location but I can't locate the exact problems.. I would love some help.. Thanks! (:

import React from 'react';
import './App.css';
import Addroom from './components/Addroom.js';
import Boxroom from './components/Boxroom.js';
import Room from './components/Room.js';
import {BrowserRouter as Router,Switch,Route,Link} from 'react-router-dom';
import 'bootstrap/dist/css/bootstrap.min.css';

state = {
  roomsList: [],
  isActive: false,
  myFilledRoom: []
};

handleShow = () => {
  this.setState({ isActive: true });
};

handleHide = () => {
  this.setState({ isActive: false });
};

create = r => {
  this.setState({
    roomsList: [...this.state.roomsList, r],
    isActive: false
  });
};

FilledRoom = () => {

  this.setState({
   Room:[...this.state.myFilledRoom]
  })
};

function App() { 
 return (
   <div className="backGroundMain" style={{backgroundColor: "lightseagreen", height: "600px", width: "850px"}}>
        <h1 style={{backgroundColor: "aquamarine", height: "40px", width: "270px", borderRadius: "5px", border: "2px", margin: "15px"}} >My Smart House</h1>

<h1>My Smart House</h1>

<Router>

 <div className="row">

   <div className="col-6"><Link to='/Boxroom'>My Rooms</Link></div>
   <div className="col-6"><Link to='/'>Homepage</Link></div>

   </div>

<Switch>


<Route exact path='/' component={()=>{return <App/>}}/>
<Route exact path='/Boxroom' component={()=>{return <Boxroom FilledRoom={Room}/>}}/>

        {this.state.roomsList.map((element, key) => {
          return (
            <Room
              id={key + 1}
              key={key}
              r={element.room}
              rt={element.roomType}
              ct={element.colorType}
              sr={element.boxColor}
            />
          );
        })}

        {this.state.isActive ? (
          <Addroom add={this.create} />
        ) : (
          <button style={{backgroundColor: "aquamarine", height: "20px", width: "60px", borderRadius: "5px", border: "2px"}} onClick={this.handleShow}>Create</button>
        )}
      </div>


</Switch>

</Router>


    </div>
 )
 }
export default App;