Simple DI example

index.ts

import 'reflect-metadata';

const INSTANCE = Symbol('Getter for injectable instance');

function Injectable(service: any) {
    const paramtypes: any[] = Reflect.getMetadata("design:paramtypes", service) || [];

    const dependencies = paramtypes.map(type => type[INSTANCE]);

    if (dependencies.some(value => value === undefined)) {
        throw new Error('Unknown dependency: ???');
    }

    service[INSTANCE] = new service(...dependencies);

    return service;
}

@Injectable
class Logger {
    log(msg: string) {
        console.log(msg)
    }
}

@Injectable
class A {
    constructor(private logger: Logger){
    }

    writeLog() {
        this.logger.log(`It works!`);
    }
}

// @ts-ignore
A[INSTANCE].writeLog();

package.json

{
  "scripts": {
    "test": "node -r ts-node/register index.ts"
  },
  "dependencies": {
    "@types/node": "^12.0.1",
    "reflect-metadata": "^0.1.13",
    "ts-node": "^8.1.0",
    "typescript": "^3.4.5"
  }
}

tsconfig.json

{
  "compilerOptions": {
    /* Basic Options */
    "target": "es2017",
    "module": "commonjs",

    /* Experimental Options */
    "experimentalDecorators": true,
    "emitDecoratorMetadata": true
  }
}