Injeca

Pure functional programming (means no class and extra wrappers and containers) based dependency injection with application lifecycle management.

Heavily inspired by uber/fig and uber/dig in Golang ecosystem.

Installation

npm install injeca
pnpm add injeca
bun add injeca
ni injeca
yarn add injeca

Basic usage

injeca ships with a global singleton container exposed as injeca. You can register providers, declare their dependencies, and run invocations once everything is ready.

import { createServer } from 'node:http'

import { injeca, lifecycle } from 'injeca'

// Providers return a value once and are cached inside the container.
const config = injeca.provide('config', () => ({ port: 3000 }))

const server = injeca.provide({
  dependsOn: { config, lifecycle },
  async build({ dependsOn }) {
    const { config, lifecycle } = dependsOn
    const app = createServer()

    lifecycle.appHooks.onStart(() => app.listen(config.port))
    lifecycle.appHooks.onStop(() => app.close())

    return app
  },
})

injeca.invoke({
  dependsOn: { server },
  async callback({ server }) {
    // eslint-disable-next-line no-console
    console.log('HTTP server ready:', await server.address())
  },
})

await injeca.start()

process.once('SIGINT', async () => {
  await injeca.stop()
})

Manual containers

If you need multiple containers (for tests or per-request scopes), create them explicitly and pass the container reference into provide, invoke, start, and stop.

import { createContainer, invoke, provide, start, stop } from 'injeca'

const container = createContainer()

const token = provide(container, 'token', () => crypto.randomUUID())

invoke(container, {
  dependsOn: { token },
  // eslint-disable-next-line no-console
  callback: ({ token }) => console.log('token', token),
})

await start(container)
await stop(container)

License

MIT