feat: Add support for region us-east-4 (#13)

* feat: Add support for region us-east-4

* Fix invalid URL when no region is specified

Author: Alex Plischke

src/index.ts

@@ -3,17 +3,19 @@ import FormData from "form-data";
 import * as stream from "stream";
 
 // The Sauce Labs region.
-export type Region = 'us-west-1' | 'eu-central-1' | 'staging';
+export type Region = 'us-west-1' | 'us-east-4' | 'eu-central-1' | 'staging';
 
 const apiURLMap = new Map<Region, string>([
     ['us-west-1', 'https://api.us-west-1.saucelabs.com/v1/testcomposer'],
+    ['us-east-4', 'https://api.us-east-4.saucelabs.com/v1/testcomposer'],
     ['eu-central-1', 'https://api.eu-central-1.saucelabs.com/v1/testcomposer'],
     ['staging', 'https://api.staging.saucelabs.net/v1/testcomposer']
   ]
 );
 
 const appURLMap = new Map<Region, string>([
     ['us-west-1', 'https://app.saucelabs.com'],
+    ['us-east-4', 'https://app.us-east-4.saucelabs.com'],
     ['eu-central-1', 'https://app.eu-central-1.saucelabs.com'],
     ['staging', 'https://app.staging.saucelabs.net']
   ]
@@ -78,7 +80,7 @@ export class TestComposer {
 
   constructor(opts: Options) {
     this.opts = opts;
-    this.url = apiURLMap.get(opts.region) || 'us-west-1';
+    this.url = apiURLMap.get(opts.region) || apiURLMap.get('us-west-1') as string;
     this.requestConfig = {auth: {username: this.opts.username, password: this.opts.accessKey}, headers: opts.headers};
   }