Callbacks ≠ passing functions as arguments. Callbacks (in the node sense) is passing a single function as the final argument which will be called exactly once w

Callbacks ≠ passing functions as arguments. Callbacks (in the node sense) is passing a single function as the final argument which will be called exactly once with an error or result. The function passed to _.each is used to access the elements of an array. It is called once for each element. It is used as a mechanism to pass a block of code to _.each, not to get a result from _.each.