Feature request: add promise.with

[jakub-bochenski]

I'd like to be able to pass some context object (e.g. a pre-initializer logger) along the promise chain.
Bluebird has a bind() method that does that.

I think implementing this would be rather simple, the question is how to make it work with Java syntax.

Closure-scope is not adequate here, as I want the same logger to be shared end-to-end and not only in the steps defined in current method.

[naugtur]

Since this is a port of when.js the method in question should be this:
https://github.com/cujojs/when/blob/master/docs/api.md#promisewith

[adrianluisgonzalez]

Thanks for the suggestion @naugtur, I haven't looked at when.js in quite a while.

Do either of you want to take a stab at adding Promise.with(thisArg)?

[jakub-bochenski]

I'd be willing to try and implement this, but I'm not sure how to handle the fact that Java doesn't seem to have anything analogous to Function.apply() in JS

My first attempt to work around this involves adding methods accepting a BiFunction<T,C, ...>in addition to regular Function<T, ... >, I'm not sure if this is adequate though.

interface ContextualThenable<T, C>
        extends Thenable<T> {

    default <U> Thenable<U> then(BiFunction<T, C, ? extends Thenable<U>> onFulfilled) {
        return then(onFulfilled, null);
    }

    <U> Thenable<U> then(BiFunction<T, C, ? extends Thenable<U>> onFulfilled,
            BiFunction<Throwable, C, ? extends Thenable<U>> onRejected);

    // unbinds context
    Thenable<T> with();
}

in simplest case you'd bind the context using this method:

interface Thenable<T> {
 //...
    <C> ContextualThenable<T, C> with(C thisArg);