dm

dm.js

Dependency Injection Manager for javascript.

Introduction

dm.js is a javascript library that implements dependency injection pattern. It could work both in node or browser.

It takes care of asynchronous creating, configuring and injecting objects aka services inside of your code.

There is a good chance to keep your application design loose coupled, well structured and flexible with dependency injection pattern.

If you are not familiar with dependency injection pattern, use wiki to get more theory info.

Usage

var DM     = require("dm"),
    Async  = require("dm/lib/async/q"),
    Loader = require("dm/lib/loader/cjs"),
    dm;

dm = new DM(new Async(Q), new Loader(require), {
    parameters: {
        "logs": "/var/log/app/"
    },

    services: {
        "logger": {
            // this is where the loader must get a constructor for this service
            "path": "./src/log/logger/polylogue.js",
            
            // this is what calls dm must do on just created service
            "calls": [
            
                // '@' symbol is the link to another service from config
                [ "addHandler", ["@handler"] ]
                
            ]
        },

        "handler": {
            "path": "./src/log/handler/file.js",
            
            // this is what arguments pass to the constructor
            "arguments": [
                {
                    // '%' symbol is the getter of parameter from config (defined above)
                    // curly braces is a kinda simple templating feature (works with '@', '#' and '%')
                    "path": "%{logs}/log.txt"
                }
            ]
        }
    }
});


dm
    .get("logger")
    .then(function(logger) {
        // now we got instantiated and configured logger
        logger.info("Hello! It works!");
    });

Quick overview

DM can:

• call constructor of your object with needed arguments;
• make any calls on created object with any arguments;
• directly set some properties;
• pass as dependency another service from configuration, or its property, or its method, or its method call result;
• pass as dependency some file content (with fs.readFile in cjs, and require(text!) in amd);
• pass as dependency value of parameters, defined in configuration object;
• pass as dependency some static string with wildcards, that could be any kind of dependencies above;
• cache or always create new object;
• retrieve already created objects and work with them as cached services;
• be configured on the fly with new definitions of services;
• use custom factory for the service, to make more complex things;

Full syntax definition you can find in the wiki.

Documentation

There is a wiki for dive deep with dm usage, syntax and ideology. Also, you can check the API docs.

Contributing

All developing version are available to install from npm as dm@x.y.z-rc. To publish new release candidate (rc abbr) just do npm publish --tag x.y.z-rc and bump version in package.json x.y.z-rc0.

License

MIT