How to add multiple classes to a ReactJS Component?

Question

I am new to ReactJS and JSX and I am having a little problem with the code below.

I am trying to add multiple classes to the className attribute on eac

Answer 1

I use ES6 template literals. For example:

const error = this.state.valid ? '' : 'error'
const classes = `form-control round-lg ${error}`

And then just render it:

One-liner version: