resolver-macro

resolver-macro

This sweet.js macro will help you turn any standard callback-based function into a promise, using whichever promise library you want.

Example

Here's an example using when and the standard fs.readFile command:

when.promise( resolver(fs.readFile, 'hello_world.txt', {encoding: 'utf-8'}) );

Getting Started

To use the macro, take a look at the sweet.js project, or setup a grunt task using something like grunt-sweet.js. You can then just install this module and require it when running sweet.js.

If you are totally new to macros, I recommend reading this excellent article:

Writing Your First Sweet.js Macro by James Long

Usage

The resolver macro will match the following pattern:

resolver(FUNCITON, ARGS...)

And expand it to:

function(resolve, reject, notify) {
  FUNCTION(ARGS..., function(err, result) {
    if (err) {
      reject(err);
    }
    resolve(result);
  }
}

This allows you to wrap that resolver function in any promise library you want. It will take any arguments in ARGS... and pass them to FUNCTION, and then add on the callback handling function for you.