Mastering JavaScript Promises

Familiarizing Node.js – the Q way

When you're working with functions that make use of the Node.js callback pattern, where callbacks are in the form of function(err, result), Q provides a few advantageous service functions for adapting between them. The two most important functions are: Q.nfcall() and Q.nfapply():

• Q.nfcall(): The Node.js function call

  return Q.nfcall(FS.readFile, "foo.txt", "utf-8");

• Q.nfapply(): The Node.js function apply

  return Q.nfapply(FS.readFile, ["foo.txt", "utf-8"]);

They are both used for calling functions with the same resemblance of Node.js so that they can generate promises.