promish

Promish

     SH
      I
P R O M

The Promish module creates a wrapper around the EcmaScript 6 Promise class. It adds some of the useful features found in many of the other popular promise libraries such as Q and Bluebird. It is designed to be interchangeable with the ES6 Promise as its interface is a superset of the Promise class.

Installation

npm install promish

New Features!

• Promish.delay()
• Promish.defer()

Backlog

• TBD

Contents

• Interface
• Known Issues
• Release History

Interface

Include

var Promish = require('promish');

Instantiation

Typical use - construct with handler function

var promise = new Promish(function(resolve, reject) {
  // do something async
});

3rd Party Wrapper Mode

var promise = new Promish(Q());

Value Wrapper Mode

var promise = new Promish('Resolve Value');

Error Wrapper Mode

var promise = new Promish(new Error('This promise is rejected'));

Then

// typical use
promise
  .then(function(value) {
    // something async has completed with a value
    // here you can return a resolve value,
    // return a new Promish or throw an error (handled as rejection)
  });
  
// with onRejected...
promise.then(
  function(value) {
  },
  function(error) {
  });

Catch

// catch all
promise
  .catch(function(error) {
    // Something async has failed with an error.
    // Just like with then(), you can return a resolve value,
    // return a new Promish or throw a new error (handled as rejection)
    // You can also 'rethrow' the error by returning a new Promish with the error
  });

Defer

For compatability with the old Promise.defer() pattern...

function readAFile(filename) {
  var deferred = Promish.defer();
  
  fs.readFile(filename, function(error, data) {
    if (error) {
      deferred.reject(error);
    } else {
      deferred.resolve(data);
    }
  });
  
  return deferred.promise;
}

Known Issues

• TBD

Release History

Version	Changes
0.0.1	Initial Version
0.0.2	Promish.delay() Promish.defer()