Why is [1,2] + [3,4] = “1,23,4” in JavaScript?

Question

I wanted to add the elements of an array into another, so I tried this:

[1,2] + [3,4]

It responded with:

\"1,23,4\"
         


        

Answer 1

It's doing exactly what you asked it to do.

What you're adding together are array references (which JS converts to strings), not numbers as it seems. It's a bit like adding strings together: "hello " + "world" = "hello world"