First Attempt on an asynchronous function array handling

Async.ts

module Async {
    export function map<TIn, TOut>(input: Array<TIn>, processor: (item: TIn, after:(outputItem: TOut)=>void)=>void, returns: (output: Array<TOut>)=>void){
        var results = [];
        forEach(input, (item, index, checkIfDone)=>processor(item, function(outputItem){
            results[index] = outputItem;
            checkIfDone();
        }), function(){
            returns(results);
        });
    }

    export function filter<T>(input: Array<T>, processor: (item: T, after: (include: boolean)=>void)=>void, returns: (output: Array<T>)=>void) {
        var results = [];
        forEach(input, (item, index, checkIfDone)=>processor(item, function(include){
            if (include) {
                results.push(item);
            }
            checkIfDone();
        }), function(){
            returns(results);
        });
    }

    export function forEach<TItem>(array: Array<TItem>, processor:(item: TItem, index: number, checkIfDone: ()=>void)=>void, after: ()=>void) {
        var returned = array.length;
        array.forEach((item, index)=>processor(item, index, function() {
            returned--;
            if (returned == 0) {
                after();
            }
        }));
    }
}