Why does objectB Instanceof InterfaceA return only refers to a type, but is being used as a value here?

Question

typescript

/**
   * Reference: https://developers.google.com/api-client-library/javascript/reference/referencedocs#gapiauth2authorizeresponse
   */
  interface AuthorizeResponse {
    access_token: string;
    id_token: string;
    code: string;
    scope: string;
    expires_in: number;
    first_issued_at: number;
    expires_at: number;
    error: string;
    error_subtype: string;
  }

gAuthenticate(): void {
        gapi.auth2.authorize(this.gapiConfig, response => {
            if (response.error || response instanceof AuthorizeResponse) {

TS2693: 'AuthorizeResponse' only refers to a type, but is being used as a value here.

Google Auth API Docs

TS @type/gapi GIT repository

According to TS Docs


But in practice instanceof in TS

Why doesn't instanceof work?
Answer on Stack is the only valid comparison option?

Answer 1

Because instanceof works at runtime when there is no typescript anymore, and by and large only with classes.
So the SO answer is the only way. Official documentation https://www.typescriptlang.org/docs/handbook/advan...