The code doesn't actually work though, the very first example is broken:

    function sum(a, b) { return a + b }
    sum = promised(sum)

    var a = defer()         // make promise
    var b = sum(a, 1)
    var b = sum(b, 5)
    console.log(b)          // eventually prints => 17
    a.resolve(11)           // fulfill promise

Prints:

    [object Object]15