Main difference between map and reduce

Question

I used both methods but I am quite confused regarding the usage of both methods.

Is anything that map can do but reduce can not and vice ve

Answer 1

The map() function returns a new array through passing a function over each element in the input array.

This is different to reduce() which takes an array and a function in the same way, but the function takes 2 inputs - an accumulator and a current value.

So reduce() could be used like map() if you always .concat onto the accumulator the next output from a function. However it is more commonly used to reduce the dimensions of an array so either taking a one dimensional and returning a single value or flattening a two dimensional array etc.