1href={"#demo" + this.state.id}
2
3//You can also use ES6 string interpolation/template literals with
4//` (backticks) and ${expr} (interpolated expression),
5
6href={`#demo${this.state.id}`}
7
8source
9https://stackoverflow.com/questions/39523040/concatenating-variables-and-strings-in-react
10