input.js

export var counter = 0;

function inc_a(cb){
    console.log(counter++);
    if(counter < 100) {
        setTimeout(inc_a, 0, [ cb ]);
    } else {
        cb();
    }
}

function inc_b(){
    console.log(++counter);
    if(counter < 100) {
        setTimeout(inc_b, 0);
    }
}

inc_a(function() {
    counter = 0;
    inc_b();
});

output.js

System.register("tests/others/a", function(import_bind, export_bind, export_push) {
    return {
        deps: [ "./b" ],
        execute: function m() { // mangle m to avoid namespace issues
            "use strict";
            var counter;
            export_bind("counter", function(){ return counter });
 
            export_push("counter", counter = 0); // returns second arg
 
            function inc_a(cb){
                console.log(export_push("counter", counter++));
                if(counter < 100) {
                    setTimeout(inc_a, 0, [ cb ]);
                } else {
                    cb();
                }
            }
            
            function inc_b(){
                console.log(export_push("counter", ++counter));
                if(counter < 100) {
                    setTimeout(inc_b, 0);
                }
            }
            
            inc_a(function() {
                export_push("counter", counter = 0);
                inc_b();
            });
        }
    };
});
 
// This is what the push operation would sort-of look like
meta.execute.push = function(name, pass_through) {
    var newVal = my.exports[name](); // fetch the value to push from the export_binding
 
    // push newVal out to subscribers of `name`
 
    return pass_through;
};