Adding two arrays

Question

What's the point of using an add "+" operator instead of concatenation method on arrays. There a lot of examples in JavaScript coding challenges.For me it's useless.

Answer 1

According to MDN web docs “it is strongly recommended that the assignment operators (+, +=) are used instead of the concat() method.”

According to performance tests, the assignment operators are several times faster.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/concat

Answer 2

Michael but last and first elements are merging into one and, as a result, you need to do additional operations to separate them.

Answer 3

Sorry, I misread your question.

You can’t use the + operator for concatenation of arrays. The + operator performs a type conversion. It converts all arrays to strings. So the result of

[1,2,3] + [4,5,6]

would not be an array anymore.

Only the concat method or the spread operator are suitable for merging arrays.