fix(types): fix waitForSelector typing to not union null when appropriate (#6344)

Previously when options were defined, but no `state` key was provided,
the types would return null as an option. Even though the default state
is `visible` and shouldn't allow `null`.

Tests updated to fail appropriately and new tests added for this case.

Author: jharwig

types/types.d.ts

@@ -21,10 +21,10 @@ import { Readable } from 'stream';
 import { Serializable, EvaluationArgument, PageFunction, PageFunctionOn, SmartHandle, ElementHandleForTag, BindingSource } from './structs';
 
 type PageWaitForSelectorOptionsNotHidden = PageWaitForSelectorOptions & {
-  state: 'visible'|'attached';
+  state?: 'visible'|'attached';
 };
 type ElementHandleWaitForSelectorOptionsNotHidden = ElementHandleWaitForSelectorOptions & {
-  state: 'visible'|'attached';
+  state?: 'visible'|'attached';
 };
 
 /**

utils/generate_types/overrides.d.ts

@@ -20,10 +20,10 @@ import { Readable } from 'stream';
 import { Serializable, EvaluationArgument, PageFunction, PageFunctionOn, SmartHandle, ElementHandleForTag, BindingSource } from './structs';
 
 type PageWaitForSelectorOptionsNotHidden = PageWaitForSelectorOptions & {
-  state: 'visible'|'attached';
+  state?: 'visible'|'attached';
 };
 type ElementHandleWaitForSelectorOptionsNotHidden = ElementHandleWaitForSelectorOptions & {
-  state: 'visible'|'attached';
+  state?: 'visible'|'attached';
 };
 
 export interface Page {

utils/generate_types/test/test.ts

@@ -675,47 +675,58 @@ playwright.chromium.launch().then(async browser => {
     }
   }
 
+  type AssertCanBeNull<T> = null extends T ? true : false
+
   const frameLikes = [page, frame];
   for (const frameLike of frameLikes) {
     {
       const handle = await frameLike.waitForSelector('body');
+      const bodyAssertion: AssertType<playwright.ElementHandle<HTMLBodyElement>, typeof handle> = true;      
+      const canBeNull: AssertCanBeNull<typeof handle> = false     
+    }
+    {
+      const handle = await frameLike.waitForSelector('body', {timeout: 0});
       const bodyAssertion: AssertType<playwright.ElementHandle<HTMLBodyElement>, typeof handle> = true;
-      const canBeNull: AssertType<null, typeof handle> = false;
+      const canBeNull: AssertCanBeNull<typeof handle> = false;
     }
     {
       const state = Math.random() > .5 ? 'attached' : 'visible';
       const handle = await frameLike.waitForSelector('body', {state});
       const bodyAssertion: AssertType<playwright.ElementHandle<HTMLBodyElement>, typeof handle> = true;
-      const canBeNull: AssertType<null, typeof handle> = false;
+      const canBeNull: AssertCanBeNull<typeof handle> = false;
     }
     {
       const handle = await frameLike.waitForSelector('body', {state: 'hidden'});
       const bodyAssertion: AssertType<playwright.ElementHandle<HTMLBodyElement>, typeof handle> = true;
-      const canBeNull: AssertType<null, typeof handle> = true;
+      const canBeNull: AssertCanBeNull<typeof handle> = true;
     }
     {
       const state = Math.random() > .5 ? 'hidden' : 'visible';
       const handle = await frameLike.waitForSelector('body', {state});
       const bodyAssertion: AssertType<playwright.ElementHandle<HTMLBodyElement>, typeof handle> = true;
-      const canBeNull: AssertType<null, typeof handle> = true;
+      const canBeNull: AssertCanBeNull<typeof handle> = true;
     }
-
     {
       const handle = await frameLike.waitForSelector('something-strange');
       const elementAssertion: AssertType<playwright.ElementHandle<HTMLElement|SVGElement>, typeof handle> = true;
-      const canBeNull: AssertType<null, typeof handle> = false;
+      const canBeNull: AssertCanBeNull<typeof handle> = false;
     }
+    {
+      const handle = await frameLike.waitForSelector('something-strange', {timeout: 0});
+      const elementAssertion: AssertType<playwright.ElementHandle<HTMLElement|SVGElement>, typeof handle> = true;
+      const canBeNull: AssertCanBeNull<typeof handle> = false;      
+    }    
     {
       const state = Math.random() > .5 ? 'attached' : 'visible';
       const handle = await frameLike.waitForSelector('something-strange', {state});
       const elementAssertion: AssertType<playwright.ElementHandle<HTMLElement|SVGElement>, typeof handle> = true;
-      const canBeNull: AssertType<null, typeof handle> = false;
+      const canBeNull: AssertCanBeNull<typeof handle> = false;
     }
     {
       const state = Math.random() > .5 ? 'hidden' : 'visible';
       const handle = await frameLike.waitForSelector('something-strange', {state});
       const elementAssertion: AssertType<playwright.ElementHandle<HTMLElement|SVGElement>, typeof handle> = true;
-      const canBeNull: AssertType<null, typeof handle> = true;
+      const canBeNull: AssertCanBeNull<typeof handle> = true;
     }
   }