DIToolkit

Problem

There are various projects solving dependency injection for NodeJS. All of them are quire opinioneted and most apply Angular way - where target of injection decide about dependencies and they can be overriden in some config.

Also non of them appreciate that DI is most useful in node for promised/deferred dependencis.

Installation

npm i --save ditoolkit

Usage

Functions - on example of Express Middleware

// module1

module.export = function IWantToBeTestable(dependency1, dependancy2, dependancy3, req, res, next, id) {
    ...
}

// module 2
const module1 = require('./module1');
require('ditoolkit');

app.user(module1.injected(null, 123, {config:1}, Promise.resolve('whatever')));

Method injected and it synchronous version (not supporting promises) inject are added to Function prototype. Once you call them you'd get version of the function with bound thisArg and dependencies. Dependencies will be prefixed to later arguments (like you can see in function declaration).

Classes

const DI = require('ditoolkit');

class A {
    test(depencency1, someArg) { ... }
}

let a = new A();

DI.decorate(a, [sharedDependnecy1]);

class B {
    test() { ... },
    test2(dependency1) { ... },
    test3(dependency1, dependency2, someArg) { ... }
}

let B = new A();

DI.decorate(a, [sharedDependnecy1], {
    test2: [],
    test3: [sharedDepenency2]
});

Also

See test for details.

License

MIT