Using a global variable in node.js to inject dependencies

Question

I am starting a long-term project based on node.js and therefore I am looking based on a solid DI system. Although node.js in its core implies the use of a simple require () module for wiring components, I believe that this approach is not suitable for a large project (for example, the required modules in each file are not supported, tested or dynamic). A.

Now I have done my research before posting this question, and I found out some interesting DI libraries for node.js (see wire.js , dependable.js )

However, for maximum simplicity and minimal repetition, I came up with my proposal for implementing DI:

• you have a di.js module that acts like a container and is initialized by specifying a json file that stores a map of dependency names and their corresponding .js files. this already provides a dynamic character for DI, since you can easily change test / dev dependencies. a container can return dependencies using the inject () function, which finds a mapping of dependencies and calls require () with it.

• for simplicity, the module is assigned to a global variable, i.e. global. $ di, so any file in the project can use a container / injector by calling $ di.inject ()

here is the gist of the implementation:

di.js:

module.exports = function(path) {

    this.deps = require(path);

    return {
        inject: function(name) {

                if (!deps[name])    
                    throw new Error('dependency "' + name + '" isn\'t registered');
                return require(deps[name]);

        }


    };

};     

json dependency configuration file:

{
    "vehicle": "lib/jetpack",
    "fuel": "lib/benzine",
    "octane": "lib/octane98"
}

initialize $ di in the js main file according to dev / test mode:

var path = 'dep-map-' + process.env.NODE_ENV + '.json;
$di = require('di')(path);

use it in some file:

var vehicle = $di.inject('vehicle');
vehicle.go();

, , $di; , , , .

- ?

!

Answer 1

.

node, , var, global, . global.varname. :

vehicle = "jetpack"
fuel = "benzine"
console.log(vehicle) // "jetpack"
console.log(global.fuel) // "benzine"

, var, .

var vehicle = "car"
console.log(vehicle) // "car"
console.log(global.vehicle) // "jetpack"

, , $di = require('di')(path) ( var), - . global.$di .

Answer 2

, . , , .

, . , . -, .

node.js, angular.js, .

, Fire Up!, .