Curly brackets in jQuery

Question

I found the following line in a tutorial on jQuery:

$tbody.append(`<tr>${abc+ def}</tr>`);

What does the curly brackets do in that case?
So, what's the purpose of this part:

${abc + def}

Answer 1

This feature is not related to jQuery and is called template literal . It is a new feature, appeared in ES6 . It will evaluate the ${abc + def} and put the value in the string.

This in ES6

`<tr>${abc+ def}</tr>` 

is equivalent to this in ES5

"<tr>" + (abc + def) + "</tr>"