Node.js and Express: How to return response after asynchronous operation

Question

I\'m new to Node.js, so I\'m still wrapping my head around asynchronous functions and callbacks. My struggle now is how to return a response after reading data from a file in an

Answer 1

To access a variable in a different function, when there isn't a shared scope, pass it as an argument.

You could just pass res and then access both query and send on the one variable within the function.

---

For the purposes of separation of concerns, you might be better off passing a callback instead.

Then do_search only needs to know about performing a query and then running a function. That makes it more generic (and thus reusable).

searcher.do_search(res.query, function (data) {
    res.send(...);
});

function do_search(query, callback) {
    callback(...);
}