injectdeps-config

injectdeps-config

Allows the binding of configuration constants provided by the node-config library through the injectdeps IoC container.

See the node-config documentation for how the configuration files need to be named and various other options like loading them from a yaml file instead of a json.

Eager binding

For the simplest operation you can just call the config loader with an injectdeps container as parameter. This loads all the compatible configurations from the config file and binds them as constants. By default the keys used for the binding will be the json path to the configuration.

Assuming this is your config/default.json

{
	"app": {
		"db": {
			"host": "localhost",
			"port": 1234,
			"seeds": ["8.8.8.8","8.8.4.4"]
		}
	},
  "other": {
    "foo":"bar"
  }
}

You can define your injected module like this

module.exports = require('injectdeps')(['app.db.host', 'app.db.port', 'app.db.debug'], function(host, port, debug){
  return `${host}:${port}:${debug}`;
});

When you initialise your container also import the default binder module and load it into the container:

const container = injector.getContainer();
const configLoader = require('injectdeps-config')(config, {});
const db = configLoader(container)
  .bindName('db').toObject(defaultDatabase)
  .newObject('db');

or shorter:

require('injectdeps-config')(config, {})()
  .bindName('db').toObject(defaultDatabase)
  .newObject('db');

In the above example we don't provide a container to the loader, which means a new one will be created.

Various configuration options for the binder are described below. For this you should instantiate an EagerBinder instead of using defaultEagerBinderModule

const settings = {
  log: true,
  root: 'app',
  prefix: 'cfg',
  objects: true
};
require('injectdeps-config')(config, settings)();

Binding only part of the configuration file

Use the root configuration parameter of the eager binder. This will only load children of this particular path. For our above example:

{
  root: 'app'
};

only loads the app breanch of the configuration. The keys necessary for injecting are also shortened.

require('injectdeps')(['db.host', 'db.port'], function(host, port){});

Adding a prefix to the binding key

In order to avoid collisions you can add a prefix to the binding keys. For our above example:

{
  root: 'app',
  prefix: 'cfg'
};

This makes correct biding:

require('injectdeps')(['cfg.db.host', 'cfg.db.port'], function(host, port){});

Note that there is no cfg key in the configuration json.

Binding entire objects

In addition to binding every leaf entry of the configuration, you can also bind the intermediary object by turning on objects in the EagerBinder settings.

{
  root: 'app',
  objects: true
};

This will bind to constants db.host, db.port, db.seeds but also db as the constant object

{
  host: "localhost",
  port: 1234,
  seeds: ["8.8.8.8","8.8.4.4"]
}

Binding logs

For debugging purposes, you can turn on binding logs

{
  log: true
};

This allows you to get an array of logs from the settings object after the binding is done.

console.log( settings.logs.join("\n") );

Binding 'cfg.db.host' to string 'localhost'
Binding 'cfg.db.port' to number '1234'
Binding 'cfg.db.seeds' to string[] '8.8.8.8,8.8.4.4'