We have given an expression [1, 2] + [3, 4], and the result of this expression is “1,23,4”. In this article, we will know why this weird result we get.
=> [1,2] + [3,4] => "1,23,4" => [1, 2, 3, 4] + [9, 8] => "1, 2, 3, 49, 8" =>  +  => "4" =>  +  => ""
For example: The undefined + undefined => number, undefined + object => String etc.
In the table below all the result of the addition is given
Output : In the above program, there are two arrays in which all 6 data type values are provided. We add every item of arr1 with every item of arr2 and printing the type of the result. That’s how we created the above table.