What does = +_ mean in JavaScript

Question

I was wondering what the = +_ operator means in JavaScript. It looks like it does assignments.

Example:

hexbin.radius = function(_)         


        

Answer 1

It's not =+. In JavaScript, + means change it into number.

+'32' returns 32.

+'a' returns NaN.

So you may use isNaN() to check if it can be changed into number.