Wrappy.js

Wrappy.js is a simple utility library that helps wraps your functions and methods in Promises. For those developers who often deal with Promises and Deferreds in a fluent interface, manually making a function or method return a promise quickly becomes tiresome and produces code bloat.

Wrappy simplfies this by creating a Promise proxy around each method of your methods, allowing you to focus on building your features.

Getting Started

Including it on your page

Simply include the wrappy source file on your page. Wrappy has no dependencies on other libraries or frameworks.

<script src="wrappy.js"></script>

Method on a Object as a Promise

To make your method a Promise object, you need to call wrappy.wrapMethod(), with the object and method name:

// Make myObj.myMethod a Promise proxy that replaces myMethod() with a proxy
wrappy.wrapMethod(myObj, 'myMethod');

When invoking your method, Wrappy will append a Promise object as the last argument, that can either resolve or reject:

// Your custom object
var myObj = {
    myMethod: function(name, promise) {
    
        // Simulate an asynchronous operation that completes in 5sec.
        // This could be an ajax call or something else
        setTimeout(function() {
            promise.resolve('My name is ' + name);
        }, 5000);
        
        // Returns immediately, non-blocking
        
    }
};

// You can now invoke myObj.myMethod as usual, but it's now a Promised method
myObj.myMethod('David').then(function(result) {
    console.log(result); // My name is David
});

Function as a Promise

To make a standalone function a Promise object, you need to call wrappy.wrapFunction() with the function to wrap and assign the result back from Wrappy to your original function:

// Make myFunction a Promise proxy that replaces reassigns itself
myFunction = wrappy.wrapFunction(myFunction);

Then call your function as usual:

function myFunction(promise) {
    // do async stuff...
    promise.reject('Some reason why the async operation failed');
}

myFunction().then(function(result) {
    console.log(result); // 'Some reason why the async operation failed'
});