promisables.js

// My Promisable's library provides two forms of use, one looks mostly like typical promises/A+ a'la Q and bluebird.  
// The other looks more like callbacks.  This gist shows examples of the two that are semantically equivalent.
// In practice, you wouldn't normally chain Promisables in the callback style to connect success and error handlers the way
// you do with the promises with then/catch/finally.

Assuming:
    var Promisable = require('promisable');

Then: 
    .then(function(V){ … })

    (function(E,V){ if (E) throw E; … })

ThenPromise:
    .thenPromise(function(R){ … })

    .then(function(V){ return Promisable(function(R){ … })})

    (function(E,V){ if (E) throw E; return Promisable(function(R){ … })})

Catch:
    .catch(function(E){ … })

    (function(E){ if (!E) return; … })

Finally: (has no equivalent)
    .finally(function(){ … })

// Promisable's handle errors some what more strictly then most promises, in that if your promisable is rejected
// and you don't deal with the error an exception will be thrown.  eg

Promisable.reject(); // throws an exception at nextTick
Promisable.reject().catch(function(E){ … }); // ok
Promisable.reject()(function(E,V){ … }); // also ok
Promisable.reject().then(function(V){ … }); // throws an exception
Promisable.reject().then(function(V){ … }).catch(function(E){ … }); // ok
Promisable.reject().catch(function(E){ … }).then(function(V){ … }); // also ok, but weird
Promisable.fulfill().then(function(V){ return Promisable.reject() }); //throws an exception
Promisable.reject().finally(function(E,V){ … }); // throws an exception
Promisable.reject().catch(function(E){ … }).finally(function(E,V){ … }); // ok