chore: enhance client-related typings (#1227)

* Enhance client-related typings

The MailService has a method to set a client, but it isn't exposed in
typings. Adding this so there is an easier way to customize underlying
agents used (for keep-alive and other connection-pooling settings)
without having compilation problems (or subverting the type system by
just using 'any')

packages/client/src/client.d.ts

@@ -46,5 +46,8 @@ declare class Client {
   request(data: ClientRequest, cb?: (err: ResponseError, response: [ClientResponse, any]) => void): Promise<[ClientResponse, any]>;
 }
 
-declare const client: Client & { Client: typeof Client };
+declare const client: Client;
+// @ts-ignore
 export = client
+
+export {Client};

packages/helpers/classes/request.d.ts

@@ -1,3 +1,5 @@
+import * as https from 'https';
+
 type HttpMethod = 'get'|'GET'|'post'|'POST'|'put'|'PUT'|'patch'|'PATCH'|'delete'|'DELETE';
 
 export default interface RequestOptions<TData = any, TParams = object> {
@@ -7,4 +9,5 @@ export default interface RequestOptions<TData = any, TParams = object> {
     qs?: TParams;
     body?: TData;
     headers?: object;
+    httpsAgent?: https.Agent;
 }

packages/mail/src/mail.d.ts

@@ -1,3 +1,4 @@
+import {Client} from "@sendgrid/client";
 import {ClientResponse} from "@sendgrid/client/src/response";
 import {ResponseError} from "@sendgrid/helpers/classes";
 import {MailDataRequired} from "@sendgrid/helpers/classes/mail";
@@ -8,6 +9,11 @@ declare class MailService {
    */
   setApiKey(apiKey: string): void;
 
+  /**
+   * Client to use for invoking underlying API
+   */
+  setClient(client: Client): void;
+
   /**
    * Twilio Email Auth passthrough for convenience.
    */

test/typescript/client.ts

@@ -1,4 +1,5 @@
 import Client = require("@sendgrid/client");
+import * as https from 'https';
 
 // Test setApiKey() method
 Client.setApiKey("MY_SENDGRID_API_KEY");
@@ -11,7 +12,8 @@ Client.setDefaultHeader({
 // Test setDefaultRequest() method
 Client.setDefaultRequest({
   url: "/test",
-}).setDefaultRequest("method", "POST");
+}).setDefaultRequest("method", "POST")
+  .setDefaultRequest('httpsAgent', new https.Agent())
 
 // Test createHeaders() method
 Client.createHeaders({

test/typescript/mail.ts

@@ -1,8 +1,12 @@
+import { Client } from "@sendgrid/client";
 import sgMail = require("@sendgrid/mail");
 
 // Test setApiKey() method
 sgMail.setApiKey("MY_SENDGRID_API_KEY");
 
+// Test setClient() method
+sgMail.setClient(new Client());
+
 // Test setSubstitutionWrappers() method
 sgMail.setSubstitutionWrappers("{{", "}}")