RequireJS, Circular Dependencies and Exports “Magic” Method

问题

I've been trying to get RequireJS set up to handle circular dependencies using the special 'exports' magic module as recommended by James Burke's answer to this question.

Following the example given by @jrburke in that question:

define("Employee", ["exports", "Company"], function(Company) {
    function Employee(name) {
        this.name = name;
        this.company = new Company.Company(name + "'s own company");
    };
    exports.Employee = Employee;
});
define("Company", ["exports", "Employee"], function(Employee) {
    function Company(name) {
        this.name = name;
        this.employees = [];
    };
    Company.prototype.addEmployee = function(name) {
        var employee = new Employee.Employee(name);
        this.employees.push(employee);
        employee.company = this;
    };
    exports.Company = Company;
});

jsfiddle

The problem is that using his own example, the exports module is undefined, and therefore exports.Employee and exports.Company don't set. If I try to include exports as an argument of the define callback functions, it simply initializes in both cases as empty and does not carry the constructor functions it was assigned.

What am I doing wrong?

EDIT: Through trial and error, I got the above code working at: http://jsfiddle.net/jpk45vow/4/. Can anyone explain why it works, because it makes no sense to me.

回答1:

Edit: I couldn't find more info about the magic exports method. I could, however, mimic its intended behavior with a dummy "Container" module. See it in this fiddle: http://jsfiddle.net/amenadiel/a7thxz98/

console.log("start");

define("Container",function() {
    var Container={};
    return Container;
});


define("Employee", ["Container"], function(Container) {
    var Employee= function(name) {
        this.name = name;
        this.company = new Container.Company(name + "'s own company");
    };
    Container.Employee = Employee;
});

define("Company", ["Container"], function(Container) {
    var Company=function(name) {
        this.name = name;
        this.employees = [];
    };
    Company.prototype.addEmployee = function(name) {
        var employee = new Container.Employee(name);
        this.employees.push(employee);
        employee.company = this;
    };
    Container.Company = Company;
});

define("main", ["Container","Employee","Company" ], function ( Container) {
    var john = new Container.Employee("John");
    var bigCorp = new Container.Company("Big Corp");
    bigCorp.addEmployee("Mary");
    console.log(bigCorp);
});

require(["main"]);

来源：https://stackoverflow.com/questions/28193382/requirejs-circular-dependencies-and-exports-magic-method

标签

javascript

requirejs

circular-dependency