DI - Scope-Aware Dependency Injection

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Simple generic dependency injection library for TypeScript.

Some features:

• Registers classes, factories, values, and functions.
• Supports synchronous and asynchronous dependency graphs.
• Supports singleton and transient lifetimes.
• Supports injection tokens, qualified types, explicit provided base classes, and scope-local registrations.
• Supports standard ECMAScript decorators but also works without decorators.
• Very small footprint.

Intentionally not supported:

• Legacy TypeScript decorators.
• Property or setter injection.

For hierarchy, ownership and disposal this library uses @kayahr/scope.

Installation

npm install @kayahr/di
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Usage

Basic example with decorators:

import { injectable, injector } from "@kayahr/di";

@injectable
class MathService {
    public add(a: number, b: number): number {
        return a + b;
    }
}

@injectable({ inject: [ MathService ] })
class Component {
    public constructor(private readonly mathService: MathService) {}

    public run(): void {
        console.log(this.mathService.add(1, 2));
    }
}

injector.getSync(Component).run();
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Basic example without decorators:

import { injector } from "@kayahr/di";

class MathService {
    public add(a: number, b: number): number {
        return a + b;
    }
}
injector.setClass(MathService);

class Component {
    public constructor(private readonly mathService: MathService) {}

    public run(): void {
        console.log(this.mathService.add(1, 2));
    }
}
injector.setClass(Component, { inject: [ MathService ] });

injector.getSync(Component).run();
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If you want an isolated injector instance, create one explicitly:

import { Injector } from "@kayahr/di";

const app = new Injector();
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The methods on Injector mirror the default injector instance. The injectable decorator is also available on the instance itself:

import { Injector } from "@kayahr/di";

const appInjector = new Injector();

@appInjector.injectable
class AppService {}
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Documentation

• Injector
• Scopes
• Class dependencies
• Factory dependencies
• Value dependencies
• Function dependencies

See also

• @kayahr/scope documentation
• ECMAScript decorators