无法通过原型函数传递

Question

I have the following module and submodule:

// Parent module "API"
var API = function(){
    console.log('loading API');
    this.param = 12345;
}

// A method for instantiating the City module via the API
API.prototype.City = function(){
    return City(this);            // <--- Can't pass this here? 
}

// Submodule "City"
var City = function(api){
    console.log("loading City");
    console.log(api);            // <--- Just prints empty object {}
}

var api = new API();
console.log(api);
var denver = new api.City();

I would expect to be able to pass the api object into the City object by passing this when instantiating it. But it just passes an empty object.

Final output:

loading API
{ config: 12345 }
loading City
{}

Is it not possible to pass the parent module into a submodule when instantiating it?

Answer 1

I think you want

API.prototype.City = function(){
    return new City(this);
//         ^^^
}

and

…
var denver = api.City();
//              ^^^^^^^ standard *method* call