Dependency Injection
When scaling up your bot to multiple files, you may find it useful to inject dependencies into the children dispatchers instead of having to pass them around manually.
@mtcute/dispatcher provides a simple service locator that you can use to inject dependencies:
ts
// for typescript, you need to declare the dependencies
declare module '@mtcute/dispatcher' {
interface DispatcherDependencies {
db: Database
}
}
// create a root dispatcher
const dp = Dispatcher.for(tg)
// inject the database
dp.inject('db', new Database())
// or
dp.inject({ db: new Database() })
// and then add a child dispatcher
import { childDispatcher } from './file2'
dp.addChild(childDispatcher)
// file2.ts
const dp = Dispatcher.child()
dp.onNewMessage(async (ctx) => {
// the dependencies are available in dp.deps
const db = dp.deps.db
await db.saveMessage(ctx.message)
})
export const childDispatcher = dp// for typescript, you need to declare the dependencies
declare module '@mtcute/dispatcher' {
interface DispatcherDependencies {
db: Database
}
}
// create a root dispatcher
const dp = Dispatcher.for(tg)
// inject the database
dp.inject('db', new Database())
// or
dp.inject({ db: new Database() })
// and then add a child dispatcher
import { childDispatcher } from './file2'
dp.addChild(childDispatcher)
// file2.ts
const dp = Dispatcher.child()
dp.onNewMessage(async (ctx) => {
// the dependencies are available in dp.deps
const db = dp.deps.db
await db.saveMessage(ctx.message)
})
export const childDispatcher = dpINFO
You can only inject dependencies into the root dispatcher (the one created with Dispatcher.for), and they will be available in all children dispatchers.