pbj-key.md

Using PBinJKeys

For the most separation of concerns, with type safety and runtime flexibility, use the pbjKey. PBinJKeys are symbols that are used to register and retrieve services, they fake having a type, kinda like branded types. We can use this type information for convenient tokens.

Interfaces

Separate your interfaces from your implementation.

//filename=interfaces.ts
import { pbjKey } from "@pbinj/pbj";

// Define your interfaces
interface LoggerService {
  log(message: string): void;
}

interface DatabaseService {
  findUser(id: string): Promise<User>;
}

// Define your keys
export const loggerKey = pbjKey<LoggerService>("@yourservice/logger");
export const dbKey = pbjKey<DatabaseService>("@yourservice/database");

Registering Services

Register services with context.register():

// filename=services.ts
import { context } from "@pbinj/pbj";
import type { LoggerService, DatabaseService } from "./interfaces";
import { loggerKey, dbKey } from "./services";

context.register(loggerKey, LoggerService);
context.register(dbKey, DatabaseService);