Async TS classes using PVT methods

async_class.ts

// Erroneous Async Class Declaration ❌
class ConfigurationLoader {
  public config: any;

  constructor() {
    // TypeScript/Javascript Compile-time Error: Constructors cannot contain 'await'
    this.config = await fetchConfiguration();
  }
}

// Correct Async Class Declaration ✅
class ConfigurationLoader {
  private config: any;

  // This ensures that the class cannot be instantiated directly using the new keyword,
  // giving the class full control over how and when instances are created.
  private constructor(config: any) {
    this.config = config;
  }

  // This method will handle the asynchronous operation and, upon completion, will 
  // instantiate the class using the private constructor.
  public static async init(): Promise<ConfigurationLoader> {
    const config = await fetchConfiguration();
    // Since, the constructor is private, we can invoke
    // it from inside the class definition, 
    // Is this some kind of recursion in declaration ? 😅
    return new ConfigurationLoader(config);
  }
}

async function fetchConfiguration(): Promise<any> {
    // Simulate fetching configuration asynchronously
    return new Promise((resolve) => {
        setTimeout(() => resolve({ apiKey: "12345" }), 1000);
    });
}
 
//👇 Instantiating the class using static method 👇
async function main() {
  // This approach allows you to perform any asynchronous setup required before 
  // creating an instance of your class, maintaining a clean and intuitive API for class consumers.
  const configLoader = await ConfigurationLoader.init();
  console.log(configLoader);
}

main();