Dependency Injection

Bunicorn includes a very simple but usefull dependency injection system.

• Full type safety
• Circular dependency support
• Easy to use
• No decorators
• Lazy loading

How to create a dependency

import { dependency } from "@bunicorn/server";

const appConfig = dependency(() => {
  // This will be called when the dependency is requested.
  return {
    port: 3000,
    host: "localhost",
    user: "bunicorn"
  };
});

const appDB = dependency(get => {
  const config = get(appConfig); // This will get the appConfig dependency, that simple!
  const dbUrl = `postgres://${config.user}:password@${config.host}:5432/mydb`;
  return new Database(dbUrl);
});

How to consume the dependency

const getTodosRoute = router.get("/todos", async ctx => {
  const db = ctx.get(appDB); // This will get the appDB dependency
  return db.todos.findMany();
});

Usage outside of routes

function globalFunction() {
  const db = BunicornApp.getFromStore(appDB); // This will get the appDB dependency, it is the same as ctx.get(appDB)
}