console.log( == ) // ""
The output of the code console.log( + ); will be an empty string "".
In other words,  +  is equivalent to "" + "", which evaluates to "".
If you want to concatenate two arrays, you can use the concat() method instead. For example, [1, 2].concat([3, 4]) it would return a new array [1, 2, 3, 4].