[trusted-types] Properly augment global to prevent conflicts with lib… (

DefinitelyTyped#64360)

* [trusted-types] Properly augment global to prevent conflicts with lib.dom.d.ts et.all

This is the proper patern to augment global interfaces that are defined by the runtime.

The previous approach would break once `lib.dom.d.ts` declares these interfaces.

The previous approach also made it impossible for other libraries to use these types.
For example, DefinitelyTyped#60691 had to be reverted.
With proper module augmentation we can land DefinitelyTyped#60691 again.

* $ExpectError -> @ts-expect-error

types/trusted-types/index.d.ts

@@ -4,30 +4,32 @@
 //                 Damien Engels <https://github.com/engelsdamien>
 //                 Emanuel Tesar <https://github.com/siegrift>
 //                 Bjarki <https://github.com/bjarkler>
+//                 Sebastian Silbermann <https://github.com/eps1lon>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 // TypeScript Version: 3.1
 
 import * as lib from './lib';
 
 // Re-export the type definitions globally.
 declare global {
-    const TrustedHTML: typeof lib.TrustedHTML;
-    type TrustedHTML = lib.TrustedHTML;
-    const TrustedScript: typeof lib.TrustedScript;
-    type TrustedScript = lib.TrustedScript;
-    const TrustedScriptURL: typeof lib.TrustedScriptURL;
-    type TrustedScriptURL = lib.TrustedScriptURL;
+    // tslint:disable-next-line no-empty-interface -- interface to allow module augmentation
+    interface TrustedHTML extends lib.TrustedHTML {}
+    // tslint:disable-next-line no-empty-interface -- interface to allow module augmentation
+    interface TrustedScript extends lib.TrustedScript {}
+    // tslint:disable-next-line no-empty-interface -- interface to allow module augmentation
+    interface TrustedScriptURL extends lib.TrustedScriptURL {}
 
-    const TrustedTypePolicy: typeof lib.TrustedTypePolicy;
-    type TrustedTypePolicy = lib.TrustedTypePolicy;
+    // tslint:disable-next-line no-empty-interface -- interface to allow module augmentation
+    interface TrustedTypePolicy extends lib.TrustedTypePolicy {}
 
-    const TrustedTypePolicyFactory: typeof lib.TrustedTypePolicyFactory;
-    type TrustedTypePolicyFactory = lib.TrustedTypePolicyFactory;
+    // tslint:disable-next-line no-empty-interface -- interface to allow module augmentation
+    interface TrustedTypePolicyFactory extends lib.TrustedTypePolicyFactory {}
 
-    type TrustedTypePolicyOptions = lib.TrustedTypePolicyOptions;
+    // tslint:disable-next-line no-empty-interface -- interface to allow module augmentation
+    interface TrustedTypePolicyOptions extends lib.TrustedTypePolicyOptions {}
 
     // Attach the relevant Trusted Types properties to the Window object.
-    // tslint:disable-next-line no-empty-interface
+    // tslint:disable-next-line no-empty-interface -- interface to allow module augmentation
     interface Window extends lib.TrustedTypesWindow {}
 }
 

types/trusted-types/test/browser.ts

@@ -104,11 +104,11 @@ trustedHTML = trustedScript;
 // @ts-expect-error
 new TrustedHTML();
 
-// $ExpectType typeof TrustedHTML
+// @ts-expect-error
 TrustedHTML;
-// $ExpectType typeof TrustedScript
+// @ts-expect-error
 TrustedScript;
-// $ExpectType typeof TrustedScriptURL
+// @ts-expect-error
 TrustedScriptURL;
 
 // $ExpectType typeof TrustedHTML