Snippet

Protecting Object Properties with Private Identifiers and Accessors

JavaScript ECMAScript private fields marked with `#` offer true runtime privacy compared to TypeScript's `private` keyword compile-time modifier, preventing unauthorized external access even after compilation.

snippet.ts

typescript

class SecureTokenStore {
  #secretKey: string;
 
  constructor(key: string) {
    this.#secretKey = key;
  }
 
  public validate(candidate: string): boolean {
    return this.#secretKey === candidate;
  }
}
 
const store = new SecureTokenStore("super-secret-123");
console.log(store.validate("wrong-key"));

Breakdown

#secretKey: string;

Declares a hard private field enforced at runtime by the JS engine, inaccessible outside the class declaration.

return this.#secretKey === candidate;

Accesses the internal secret key safely inside a public class method.

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Protecting Object Properties with Private Identifiers and Accessors

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