TS1035

Only ambient modules can use quoted names.

Broken Code ❌

module 'global' {
  namespace globalThis {
    var signin: () => string[];
  }
}
 
this.signin();

Fixed Code ✔️

To turn a module into an ambient module, you have to prefix it with the declare keyword:

declare module 'global' {
  namespace globalThis {
    var signin: () => string[];
  }
}
 
this.signin();