@daisugi/vasa

Vasa is a minimal and unobtrusive inversion of control container.

Usage

const { vasa } = require('@daisugi/vasa');

const { container } = vasa();

class Foo {
  constructor(bar) {
    this.bar = bar;
  }
}

class B {}

container.register([
  {
    token: 'Foo',
    useClass: Foo,
    params: ['Bar'],
  },
  {
    token: 'Bar',
    useClass: Bar,
  },
]);

const foo = container.resolve('Foo');

Table of contents

• @daisugi/vasa
  • Usage
  • Install
  • Motivation
  • API
    • token
    • useClass
    • useValue
    • useFactory
    • useFactoryWithParams
    • scope
    • #list()
  • Goal
  • License

Install

Using npm:

npm install @daisugi/vasa

Using yarn:

yarn add @daisugi/vasa

Motivation

This library is a result of a series of the requirements that either were not met by other libraries of same type, or were partially met, or finally met everything but also brought an overhead not required by the project.

If you feel that any of the following requirements is close to your demand, feel free to use this library, otherwise there are many other good IoC libraries out there such as di-ninja or tsyringe, among many others that you can use.

• Should allow to create multiple instances of the container, and not share the state globally (useful when multiple packages are using it).
• The DI configuration must be abstracted from the base code, and must be able to be easily ported (Composition Root).
• Dependencies must be able easily decorated (useful to add telemetry, debug ...).
• Avoid using decorators by annotations (see STYLE_GUIDE.md pt.21).
• Support a limited set of features; singleton and not, classes, values, and factories, and not much more.

API

token

Is the name used to register the dependency, to later be resolved.

useClass

Can go along with params property, which contains tokens with which the class should be resolved.

Usage

const { vasa } = require('@daisugi/vasa');

const { container } = vasa();

class Foo {
  constructor(bar) {
    this.bar = bar;
  }
}

class Bar {}

container.register([
  {
    token: 'Foo',
    useClass: Foo,
    params: ['Bar'],
  },
  {
    token: 'Bar',
    useClass: Bar,
  },
]);

const foo = container.resolve('Foo');

useValue

Useful for storing constants.

Usage

const { vasa } = require('@daisugi/vasa');

const { container } = vasa();

container.register([
  {
    token: 'foo',
    useValue: 'text',
  },
]);

const foo = container.resolve('foo');

useFactory

Provides container as argument to the factory method.

Usage

const { vasa } = require('@daisugi/vasa');

const { container } = vasa();

class Foo {}

function bar(c) {
  return c.resolve('Foo');
}

container.register([
  {
    token: 'Foo',
    useClass: Foo,
  },
  {
    token: 'bar',
    useFactory: bar,
  },
]);

const foo = container.resolve('bar');

useFactoryWithParams

Same as useFactory, except provides params to it, instead of the container.

Usage

const { vasa } = require('@daisugi/vasa');

const { container } = vasa();

class Foo {}

function bar(foo) {
  return foo;
}

container.register([
  {
    token: 'Foo',
    useClass: Foo,
  },
  {
    token: 'bar',
    useFactoryWithParams: bar,
    params: ['Foo'],
  },
]);

const foo = container.resolve('bar');

scope

Scope can be Transient or Singleton, by default it's Singleton. Can be used along with useClass, useFactory and useFactoryWithParams. Having scope as Transient it will create a new instance every time the dependency is resolved, Singleton will reuse the already created instance.

Usage

const { vasa } = require('@daisugi/vasa');

const { container } = vasa();

class Foo {}

container.register([
  {
    token: 'Foo',
    useClass: Foo,
    scope: 'Transient',
  },
]);

const foo = container.resolve('Foo');

#list()

Get the list of the registered dependencies.

Usage

const { vasa } = require('@daisugi/vasa');

const { container } = vasa();

class Foo {}

container.register([
  {
    token: 'Foo',
    useClass: Foo,
    scope: 'Transient',
  },
]);

const manifest = container.list();

// Now you can iterate the manifest items and decorate methods.

Goal

The project aims to support the basic functionality of IoC. The functionality will be kept simple and will not be overextended.

License

MIT