Concat in an empty array in Javascript

Question

I was browsing through some code and I was wondering how this could be useful

grid.push([].concat(row));

In my understanding it is the same as

grid.push([row]);

Why the 'concat' fuss?

Answer 1

Check my variant:

let arr = [];
let tmp = [ 1, 2, '300$' ];
arr.push(...tmp);