React-router what is $?

Question

I'm trying to figure out if this is a react-router thing or just a React thing. I am talking about the $ here in their example:

react-router API

<Link to={`/users/${user.id}`} activeClassName="current">{user.name}</Link>

is the ${} a react thing? and if so what do you call it?

Answer 1

This is not a React thing.

This is a JavaScript ES6 feature:

The old way to concatenate a string :

var user = 'abc' + myuser;

ES6:

var user = `abc${myuser}`;

Answer 2

${variableName} inside backticks is just part of es6's string interpolation system that simply just embeds the value of a variable in the given string.

For more docs and examples see MDN - Template Literals