Blog · Readonly

Readonly

Readonly is used to prevent properties from being modified after they are initialized.
This is enforced at compile time, offering additional safety in your code.

interface Config {
  readonly endpoint: string;
  readonly apiKey: string;
}

const config: Config = {
  endpoint: 'https://api.example.com',
  apiKey: 'abcdef123456',
};

// config.apiKey = 'newkey'; // Error: Cannot assign to 'apiKey' because it is a read-only property.