This is a simple implementation of the Promises/A+ spec.
Example
var doSomethingAsync = new Vow(function(fulfill, reject){
setTimeout(function(){ fulfill('heyy test passed'); }, 1);
});
doSomethingAsync
.then(function(value){ return value + ' twice'; })
.then(function(value){ console.log(value); });
// prints 'heyy test passed twice'