inversify-binding-decorators

An utility that allows developers to declare InversifyJS bindings using ES2016 decorators:

Installation

You can install inversify-binding-decorators using npm:

$ npm install inversify inversify-binding-decorators reflect-metadata --save

The inversify-binding-decorators type definitions are included in the npm module and require TypeScript 2.0. Please refer to the InversifyJS documentation to learn more about the installation process.

The basics

The InversifyJS API allows us to declare bindings using a fluent API:

1import { injectable, Container } from "inversify";
2import "reflect-metadata";
3
4@injectable()
5class Katana implements Weapon {
6    public hit() {
7        return "cut!";
8    }
9}
10
11@injectable()
12class Shuriken implements ThrowableWeapon {
13    public throw() {
14        return "hit!";
15    }
16}
17
18var container = new Container();
19container.bind<Katana>("Katana").to(Katana);
20container.bind<Shuriken>("Shuriken").to(Shuriken);

This small utility allows you to declare bindings using decorators:

1import { injectable, Container } from "inversify";
2import { provide, buildProviderModule } from "inversify-binding-decorators";
3import "reflect-metadata";
4
5@provide(Katana)
6class Katana implements Weapon {
7    public hit() {
8        return "cut!";
9    }
10}
11
12@provide(Shuriken)
13class Shuriken implements ThrowableWeapon {
14    public throw() {
15        return "hit!";
16    }
17}
18
19var container = new Container();
20// Reflects all decorators provided by this package and packages them into 
21// a module to be loaded by the container
22container.load(buildProviderModule());
23

Using @provide multiple times

If you try to apply @provide multiple times:

1@provide("Ninja")
2@provide("SilentNinja")
3class Ninja {
4    // ...
5}

The library will throw an exception:

Cannot apply @injectable decorator multiple times. Please use @provide(ID, true) if you are trying to declare multiple bindings!

We throw an exception to ensure that you are are not trying to apply @provide multiple times by mistake.

You can overcome this by passing the force argument to @provide:

1@provide("Ninja", true)
2@provide("SilentNinja", true)
3class Ninja {
4    // ...
5}

Using classes, string literals & symbols as identifiers

When you invoke @provide using classes:

1@provide(Katana)
2class Katana {
3    public hit() {
4        return "cut!";
5    }
6}
7
8@provide(Ninja)
9class Ninja {
10    private _katana: Weapon;
11    public constructor(
12        katana: Weapon
13    ) {
14        this._katana = katana;
15    }
16    public fight() { return this._katana.hit(); };
17}

A new binding is created under the hood:

1container.bind<Katana>(Katana).to(Katana);
2container.bind<Ninja>(Ninja).to(Ninja);

These bindings use classes as identidiers but you can also use string literals as identifiers:

1let TYPE = {
2    IKatana: "Katana",
3    INinja: "Ninja"
4};
5
6@provide(TYPE.Katana)
7class Katana implements Weapon {
8    public hit() {
9        return "cut!";
10    }
11}
12
13@provide(TYPE.Ninja)
14class Ninja implements Ninja {
15
16    private _katana: Weapon;
17
18    public constructor(
19        @inject(TYPE.Katana) katana: Weapon
20    ) {
21        this._katana = katana;
22    }
23
24    public fight() { return this._katana.hit(); };
25
26}

You can also use symbols as identifiers:

1let TYPE = {
2    Katana: Symbol("Katana"),
3    Ninja: Symbol("Ninja")
4};
5
6@provide(TYPE.Katana)
7class Katana implements Weapon {
8    public hit() {
9        return "cut!";
10    }
11}
12
13@provide(TYPE.Ninja)
14class Ninja implements Ninja {
15
16    private _katana: Weapon;
17
18    public constructor(
19        @inject(TYPE.Katana) katana: Weapon
20    ) {
21        this._katana = katana;
22    }
23
24    public fight() { return this._katana.hit(); };
25
26}

Fluent binding decorator

The basic @provide decorator doesn't allow you to declare contextual constraints, scope and other advanced binding features. However, inversify-binding-decorators includes a second decorator that allows you to achieve access the full potential of the fluent binding syntax:

1import { injectable, Container } from "inversify";
2import { fluentProvide, buildProviderModule } from "inversify-binding-decorators";
3
4let TYPE = {
5    Weapon : "Weapon",
6    Ninja: "Ninja"
7};
8
9@fluentProvide(TYPE.Weapon).whenTargetTagged("throwable", true).done();
10class Katana implements Weapon {
11    public hit() {
12        return "cut!";
13    }
14}
15
16@fluentProvide(TYPE.Weapon).whenTargetTagged("throwable", false).done();
17class Shuriken implements Weapon {
18    public hit() {
19        return "hit!";
20    }
21}
22
23@fluentProvide(TYPE.Ninja).done();
24class Ninja implements Ninja {
25
26    private _katana: Weapon;
27    private _shuriken: Weapon;
28
29    public constructor(
30        @inject(TYPE.Weapon) @tagged("throwable", false) katana: Weapon,
31        @inject(TYPE.Weapon) @tagged("throwable", true) shuriken: ThrowableWeapon
32    ) {
33        this._katana = katana;
34        this._shuriken = shuriken;
35    }
36
37    public fight() { return this._katana.hit(); };
38    public sneak() { return this._shuriken.throw(); };
39
40}
41
42var container = new Container();
43container.load(buildProviderModule());

One of the best things about the fluent decorator is that you can create aliases to fit your needs:

1let provideThrowable = function(identifier, isThrowable) {
2	return provide(identifier)
3		      .whenTargetTagged("throwable", isThrowable)
4		      .done();
5};
6
7@provideThrowable(TYPE.Weapon, true)
8class Katana implements Weapon {
9    public hit() {
10        return "cut!";
11    }
12}
13
14@provideThrowable(TYPE.Weapon, false)
15class Shuriken implements Weapon {
16    public hit() {
17        return "hit!";
18    }
19}

Another example:

1const provideSingleton = (identifier: any) => {
2    return fluentProvide(identifier)
3        .inSingletonScope()
4        .done();
5};
6
7@provideSingleton(TYPE.Weapon)
8class Shuriken implements Weapon {
9    public hit() {
10        return "hit!";
11    }
12}

Using @fluentProvide multiple times

If you try to apply @fluentProvide multiple times:

1let container = new Container();
2
3const provideSingleton = (identifier: any) => {
4    return fluentProvide(identifier)
5        .inSingletonScope()
6        .done();
7};
8
9function shouldThrow() {
10    @provideSingleton("Ninja")
11    @provideSingleton("SilentNinja")
12    class Ninja {}
13    return Ninja;
14}

The library will throw an exception:

Cannot apply @fluentProvide decorator multiple times but is has been used multiple times in Ninja Please use done(true) if you are trying to declare multiple bindings!

We throw an exception to ensure that you are are not trying to apply @fluentProvide multiple times by mistake.

You can overcome this by passing the force argument to done():

1
2const provideSingleton = (identifier: any) => {
3    return fluentProvide(identifier)
4    .inSingletonScope()
5    .done(true); // IMPORTANT!
6};
7
8function shouldThrow() {
9    @provideSingleton("Ninja")
10    @provideSingleton("SilentNinja")
11    class Ninja {}
12    return Ninja;
13}
14let container = new Container();
15container.load(buildProviderModule());

The auto provide utility

This library includes a small utility apply to add the default @provide decorator to all the public properties of a module:

Consider the following example:

1import * as entities from "../entities";
2
3let container = new Container();
4autoProvide(container, entities);
5let warrior = container.get(entities.Warrior);
6expect(warrior.fight()).eql("Using Katana...");

The contents of the entities.ts file are the following:

1export { default as Warrior } from "./warrior";
2export { default as Katana } from "./katana";

The contents of the katana.ts file are the following:

1class Katana {
2    public use() {
3        return "Using Katana...";
4    }
5}
6
7export default Katana;

The contents of the warrior.ts file are the following:

1import Katana from "./katana";
2import { inject } from "inversify";
3
4class Warrior {
5    private _weapon: Weapon;
6    public constructor(
7        // we need to declare binding because auto-provide uses
8        // @injectable decorator at runtime not compilation time
9        // in the future maybe this limitation will disappear
10        // thanks to design-time decorators or some other TS feature
11        @inject(Katana) weapon: Weapon
12    ) {
13        this._weapon = weapon;
14    }
15    public fight() {
16        return this._weapon.use();
17    }
18}
19
20export default Warrior;

Support

If you are experience any kind of issues we will be happy to help. You can report an issue using the issues page or the chat. You can also ask questions at Stack overflow using the inversifyjs tag.

If you want to share your thoughts with the development team or join us you will be able to do so using the official the mailing list. You can check out the wiki and browse the documented source code to learn more about InversifyJS internals.

Acknowledgements

Thanks a lot to all the contributors, all the developers out there using InversifyJS and all those that help us to spread the word by sharing content about InversifyJS online. Without your feedback and support this project would not be possible.

License

License under the MIT License (MIT)

Copyright © 2016 Remo H. Jansen

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.

IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.