Added setState call in app.js

src/App.js

@@ -18,16 +18,18 @@ class BooksApp extends React.Component {
   componentDidMount() {
     getAll().then((books) => {
       this.setState({ books })
-      console.log(this.state.books[0].id)
     })
   }
 
   onSelectChange = (e) => {
     const id = e.target.name
-    const shelf = e.target.value
-//    console.log(id, shelf)
-    const changeShelf = this.state.books.filter((book, id) => book.id === id)
+    const newShelf = e.target.value
+    console.log(id, newShelf)
+    const changeShelf = this.state.books.filter((book) => { return book.id === id})
     console.log("changeShelf: ", changeShelf)
+    this.setState({
+      changeShelf.shelf: changeShelf.newShelf
+    })
   }
 
   render() {