Typescript: improves chaining experience

lib/credentials/credential_provider_chain.d.ts

@@ -8,7 +8,7 @@ export class CredentialProviderChain extends Credentials {
     /**
      * Resolves the provider chain by searching for the first set of credentials in providers.
      */
-    resolve(callback:(err: AWSError, credentials: Credentials) => void): any;
+    resolve(callback:(err: AWSError, credentials: Credentials) => void): CredentialProviderChain;
     /**
      * Returns a list of credentials objects or functions that return credentials objects. If the provider is a function, the function will be executed lazily when the provider needs to be checked for valid credentials. By default, this object will be set to the defaultProviders.
      */

ts/tsconfig.json

@@ -1,5 +1,7 @@
 {
     "compilerOptions": {
+        "noImplicitAny": true,
+        "strictNullChecks": true,
         "allowJs": true,
         "target": "es5",
         "module": "commonjs",
@@ -10,4 +12,4 @@
         ],
         "noEmit": true
     }
-}
+}