Cannot Denodeify Methods In Node-ftp Module

I am new to both node.js and promise style function call. By looking at an denodeify example at http://runnable.com/Ulatc0QnzUgUAAAK/adapting-node-js-with-q-for-promises, I am tryi

Solution 1:

When you pass

ftpClient.list

to Q.denodefiy, you are getting the function object, list from the ftpClient object. It will be just a function and the relationship with the parent is lost. This is important because, the bound function list might be dependent on the ftpClient object. So, you must make sure that link is not broken.

Quoting from the Q.denodeify docs,

Note that if you have a method that uses the Node.js callback pattern, as opposed to just a function, you will need to bind its this value before passing it to denodeify, like so:

var Kitty = mongoose.model("Kitty");
var findKitties = Q.denodeify(Kitty.find.bind(Kitty));

The better strategy for methods would be to use Q.nbind, as shown below.

So, you can fix your code in two ways,

1. Using Q.denodeify and Function.prototype.bind, like this

   var ftpList = q.denodeify(ftpClient.list.bind(ftpClient));
   

2. Using Q.nbind, like this

   var ftpList = q.nbind(ftpClient.list, ftpClient);
   

Solution 2:

you need to use q.nbind

q.nbind(ftpClient.list, ftpClient);