Fix return values for webdriver config hooks (#29594)

* Export the configuration interface
Added class for the server instead of interface
Added TS lint file and fixed errors

* Fix promise values for hooks

* Minor change

types/webdriverio/index.d.ts

@@ -4,6 +4,7 @@
 //                 Tim Brust <https://github.com/timbru31>
 //                 Fredrik Smedberg <https://github.com/fsmedberg-tc>
 //                 Tanvir ul Islam <https://github.com/tanvirislam06>
+//                 Dave Parslow <https://github.com/daveparslow>
 //                 Phil Leger <https://github.com/phil-lgr>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 
@@ -343,65 +344,66 @@ declare namespace WebdriverIO {
     }
 
     interface Hooks {
-        onError?<T>(error: Error): Promise<T> & undefined;
+        onError?(error: Error): Promise<any> | void;
 
-        onPrepare?<T>(
+        onPrepare?(
             config: Options,
             capabilities: DesiredCapabilities
-        ): Promise<T> & undefined;
+        ): Promise<any> | void;
 
-        onComplete?<T>(exitCode: number): Promise<T> & undefined;
+        onComplete?(exitCode: number): Promise<any> | void;
 
-        before?<T>(
+        before?(
             capabilities: DesiredCapabilities,
             specs: string[]
-        ): Promise<T> & undefined;
+        ): Promise<any> | undefined;
 
-        beforeCommand?<T>(
+        beforeCommand?(
             commandName: string,
             args: any[]
-        ): Promise<T> & undefined;
+        ): Promise<any> | void;
 
-        beforeFeature?<T>(feature: string): Promise<T> & undefined;
-        beforeHook?<T>(): Promise<T> & undefined;
-        beforeScenario?<T>(scenario: string): Promise<T> & undefined;
+        beforeHook?(): Promise<any> | void;
 
-        beforeSession?<T>(
+        beforeSession?(
             config: Options,
             capabilities: DesiredCapabilities,
             specs: string[]
-        ): Promise<T> & undefined;
+        ): Promise<any> | void;
 
-        beforeStep?<T>(step: string): Promise<T> & undefined;
-        beforeSuite?<T>(suite: Suite): Promise<T> & undefined;
-        beforeTest?<T>(test: Test): Promise<T> & undefined;
-        afterHook?<T>(): Promise<T> & undefined;
+        beforeSuite?(suite: Suite): Promise<any> | void;
+        beforeTest?(test: Test): Promise<any> | void;
+        afterHook?(): Promise<any> | void;
 
-        after?<T>(
+        after?(
             result: number,
             capabilities: DesiredCapabilities,
             specs: string[]
-        ): Promise<T> & undefined;
+        ): Promise<any> | void;
 
-        afterCommand?<T>(
+        afterCommand?(
             commandName: string,
             args: any[],
             result: any,
             error?: Error
-        ): Promise<T> & undefined;
+        ): Promise<any> | undefined;
 
-        afterScenario?<T>(scenario: any): Promise<T> & undefined;
-
-        afterSession?<T>(
+        afterSession?(
             config: Options,
             capabilities: DesiredCapabilities,
             specs: string[]
-        ): Promise<T> & undefined;
+        ): Promise<any> | void;
 
-        afterStep?<T>(stepResult: any): Promise<T> & undefined;
-        afterSuite?<T>(suite: Suite): Promise<T> & undefined;
-        afterTest?<T>(test: Test): Promise<T> & undefined;
-        afterFeature?<T>(feature: string): Promise<T> & undefined;
+        afterSuite?(suite: Suite): Promise<any> | void;
+        afterTest?(test: Test): Promise<any> | void;
+
+         // cucumber specific hooks
+         beforeFeature?(feature: string): Promise<any> | void;
+         beforeScenario?(scenario: string): Promise<any> | void;
+         beforeStep?(step: string): Promise<any> | void;
+         afterFeature?(feature: string): Promise<any> | void;
+         afterScenario?(scenario: any): Promise<any> | void;
+         afterStep?(stepResult: any): Promise<any> | void;
     }
 
     interface Options {

types/webdriverio/webdriverio-tests.ts

@@ -118,3 +118,22 @@ webdriverio
         console.log(visible); // Should return true
     })
     .end();
+
+let hooks: webdriverio.Hooks  = {};
+
+hooks = {
+  // Hooks can be a noop function
+  onPrepare: () => undefined,
+  onError() {
+    // Hooks don't have to return a value
+  }
+};
+
+hooks.onComplete = async () => {
+    // Hooks can return a promise but the promise can be void
+};
+
+hooks.afterTest = async () => {
+    // Hooks can have a promise with a result but it is not typically used
+    return false;
+};