mailgun-js: Allow sending templates (DefinitelyTyped#35871)

* Added 'template' support for sending messages with mailgun.

* Implemented suggested changes.

* Switched template variables to 'any' as otherwise they conflict with existing properties (like 'to' allowing 'string[]')

* Removed 'any'.

types/mailgun-js/index.d.ts

@@ -3,6 +3,7 @@
 // Definitions by: Sampson Oliver <https://github.com/sampsonjoliver>
 //                 Andi Pätzold <https://github.com/andipaetzold>
 //                 Jiri Balcar <https://github.com/JiriBalcar>
+//                 Ryan Leonard <https://github.com/CodeLenny>
 // Definitions: https://github.com/DefinitelyTyped/DefinitelyTyped
 // TypeScript Version: 2.3
 
@@ -113,6 +114,11 @@ declare namespace Mailgun {
             'recipient-variables'?: BatchSendRecipientVars;
         }
 
+        type SendTemplateData = SendData & {
+            template: string;
+            [templateVariable: string]: string;
+        };
+
         interface BatchSendRecipientVars {
             [email: string]: {
                 first: string;
@@ -232,7 +238,7 @@ declare namespace Mailgun {
 
     interface Messages {
         send(
-            data: messages.SendData | messages.BatchData,
+            data: messages.SendData | messages.BatchData | messages.SendTemplateData,
             callback?: (error: Error, body: messages.SendResponse) => void
         ): Promise<messages.SendResponse>;
     }

types/mailgun-js/mailgun-js-tests.ts

@@ -66,6 +66,14 @@ const arraySendData: mailgunFactory.messages.SendData = {
 
 mailgun.messages().send(arraySendData, (err, body) => {});
 
+const exampleSendDataWithTemplate: mailgunFactory.messages.SendTemplateData = {
+    to: "someone@email.com",
+    template: "my-template",
+    "v:template-variable": "foo",
+  };
+
+const exampleSendDataTemplateResponse: Promise<mailgunFactory.messages.SendResponse> = mailgun.messages().send(exampleSendDataWithTemplate);
+
 let validationResultPromise: Promise<mailgunFactory.validation.ValidateResponse>;
 validationResultPromise = mailgun.validate("foo@mailgun.net");
 validationResultPromise = mailgun.validate("foo@mailgun.net", true);