xcatalog

Simple dependency injection container for nodejs4+

Installation

$ npm install xcatalog --save

Setting up

There are to different ways to load references into the xcatalog:

Direct configuration

xcatalog.set(id, type, ref, deps)

"use strict";
 
//A.js
class A {
    constructor (str) {
        this.bar = str;
    }
}
 
function foo (a, b) {
    return a + " " + b;
}
 
//config.js
const xcatalog = require("xcatalog");
xcatalog
    .set("MY_TEXT", "constant", "BANANA")
    .set("a", "singleton", A, ["MY_TEXT"])
    .set("foo", "factory", foo, ["MY_TEXT", "MY_TEXT"]);;
 
console.log(xcatalog("a").bar); // "BANANA"
console.log(xcatalog("foo")); // "BANANA BANANA"
 

Annotations

"use strict";
 
//A.js
class A {
    constructor () {
        this.foo = "BANANA";
    }
}
 
A.$xcatalog = { id: "a", type: "singleton" };
 
//B.js
class B {
    constructor (a) {
        this.bar = a.foo;
    }
}
 
B.$xcatalog = { id: "b", type: "singleton", inject: ["a"] };
 
//config.js
const xcatalog = require("xcatalog");
 
//xcatalog.load(require("./A")).load(require("./B"));
xcatalog.load(A).load(B);
 
console.log(xcatalog("b").bar); // "BANANA"
 

Load directories

Use xcatalog.loaddir(path) to load all resouces with $catalog annotation in the given path.

This function will require every .js file in the path and sub directories.

Getting instances

"use strict";
const xcatalog = require("xcatalog");
 
//Get service instance already built with dependencies
const myService = xcatalog("myService");
 

Dealing with Promises

If any reference returns a promise the xcatalog cannot be used until is ready.

xcatalog.ready() returns a promise, that promise is fulfilled when the xcatalog is fully available or rejected is any pending promise es rejected.

"use strict";
const xcatalog = require("xcatalog");
const promise = Promise.resolve("BANANA");
 
xcatalog.set("VALUE", "constant", promise);
 
//Get service instance already builded with dependencies
xcatalog.ready().then(function () {
    console.log(xcatalog("VALUE")); // "BANANA"
});