Getting started

injecute is a dependency injection container for TypeScript without decorators. You register each service with a key, a factory (a function or a class) and the keys it depends on. The container resolves everything in the right order, and its type grows with every registration.

Install

npm

npm install injecute

pnpm

pnpm add injecute

bun

bun add injecute

deno

deno add npm:injecute

injecute is an ES module for Node.js ≥ 22.12, Deno, Bun and browsers, with no runtime dependencies. It also works without a build step.

Your first container

import { DIContainer } from 'injecute';

class Database {
  constructor(readonly url: string) {}
  query(sql: string): string[] {
    return [`${this.url}: ${sql}`];
  }
}

class UserRepository {
  constructor(private readonly db: Database) {}
  findAll(): string[] {
    return this.db.query('select * from users');
  }
}

const app = new DIContainer()
  .addInstance('dbUrl', 'postgres://localhost/app')
  .addSingleton('db', Database, ['dbUrl'])
  .addSingleton('users', UserRepository, ['db']);

const users = app.get('users'); // typed as UserRepository
users.findAll();

Open in the playground

What happened:

• addInstance('dbUrl', …) registers an existing value.
• addSingleton('db', Database, ['dbUrl']) registers a class. The container calls new Database(dbUrl) the first time db is needed, then reuses that instance.
• app.get('users') resolves users and everything it depends on. Its type is UserRepository, inferred from the registration.

Factory parameters and results are inferred from the registrations:

import { DIContainer } from 'injecute';

const app = new DIContainer()
  .addInstance('port', 8080)
  // port: number
  .addSingleton('address', (port) => `http://localhost:${port}`, ['port']);

const address = app.get('address'); // string

Mistakes are compile errors. A typo in a dependency key is reported on the key:

app.addSingleton('server', createServer, ['adress']);
// Type '"adress"' is not assignable to type 'Dependency<…>'. Did you mean '"address"'?

Next steps

• Registering services: lifetimes, optional dependencies, aliases, decoration.
• Containers, forks and modules: forks, isolated forks for tests, modules.
• Request context: the trace id, tenant and user of the current request in every service.
• Scoped state: scopes for a session, a request or a transaction, and the patterns that keep every service in the root.
• Lifecycle and dispose: releasing connections with dispose() and await using.
• Frameworks: Express, Fastify, Hono, Next.js and GraphQL; React, Vue and Solid; coming from NestJS.
• Roles: which part of your code gets which view of the container.