Require: access/list all loaded modules

Question

I'm in the situation where I have the following code:

define([
    "require",
    "./module1/module1",
    "./module2/module2",
    "./module3/module3",
    // ...
    // hundreds of modules here (with their path)
    // ...
], function (
    require,
    module1,
    module2,
    module3,
    // ...
    // hundreds of modules's name here
    // ...
) {
    var myMod = function() {

        myMap = {                            |
            "module1": new module1(),        | This is the part
            "module2": new module2(),        | I would like to
            "module3": new module3()         | optimize.
        }                                    |

    return myMod;
});

Here for each loaded module, I initialize it and push into a map. Of course the code above is not readable, maintainable and horrible.

Instead I want to do something like below:

define([
    "require",
    // ...
    // hundreds of modules here (with their path)
    // ...
], function (
    require,
    // ...
    // hundreds of modules's name here
    // ...
) {
    var myMod = function(myDict) {

        myMap = {}

        for (var elem in myDict) {
            ***myMap[elem.name] = new $corresponding-elem-referece$();*** // pseudo-code.
        }


    return myMod;
});

Basically, each of elements within myDictdictionary has a name property. Depending of the value of name I want to initialize the corresponding module and add the result into myMap object. In order to do that, I should be able to get the module reference knowing its name. And here lives my problem - I think.

This is useful to me because in this way I do not need to initialize all modules and push them into the map, if I'm not gonna use them - kind of lazy loader.

Any help or suggestion? Thanks.

Answer 1

You could scan arguments to build your map. Here is an example designed to run as-is in Node.js. Comments in the code explain what is going on.

var requirejs = require("requirejs");

var req = requirejs({});

function generic_module(module) {
    function m() {
        // Convenience so that we can distinguish instances...
        this.from_module = module.id;
    };

    // Set an `id` property on the function we return so that we can
    // match by module id rather than function name. Module.id is the
    // name by which the module is known to RequireJS.
    m.id = module.id;

    return m;
}

requirejs.define('a', ['module'], generic_module);
requirejs.define('b', ['module'], generic_module);
requirejs.define('c', ['module'], generic_module);

requirejs.define('test', ['require', 'a', 'b', 'c'], function () {

    // Create a map from module name to module value. We use the `id`
    // field we set on the module's return values to be able to map by
    // module id instead of function name.
    var name_to_value = Object.create(null);
    for (var i = 1; i < arguments.length; ++i) {
        var arg = arguments[i];
        name_to_value[arg.id] = arg;
    }

    // The myDict value should be a dictionary whose keys are module
    // ids.
    function myMod(myDict) {
        var keys = Object.keys(myDict);

        var myMap = Object.create(null);
        for (var i = 0; i < keys.length; ++i) {
            var key = keys[i];
            var value = name_to_value[key];
            myMap[key] = new value();
        }

        return myMap;
    }

    return myMod;
});

req(['test'], function (test) {
    console.log(test({'a': 1, 'b': 1}));
});