Fixed Compilation error by changing property value param to accept array of strings in select, expand, orderby methods and by adding required libraries in config.

lib/spec/core/responseHandling.d.ts

@@ -0,0 +1 @@
+export {};

lib/spec/core/urlGeneration.d.ts

@@ -0,0 +1 @@
+export {};

lib/spec/core/urlParsing.d.ts

@@ -0,0 +1 @@
+export {};

lib/src/GraphRequest.d.ts

@@ -16,9 +16,9 @@ export declare class GraphRequest {
     private urlJoin(urlSegments);
     buildFullUrl(): string;
     version(v: string): GraphRequest;
-    select(properties: string | [string]): GraphRequest;
-    expand(properties: string | [string]): GraphRequest;
-    orderby(properties: string | [string]): GraphRequest;
+    select(properties: string | string[]): GraphRequest;
+    expand(properties: string | string[]): GraphRequest;
+    orderby(properties: string | string[]): GraphRequest;
     filter(filterStr: string): GraphRequest;
     top(n: number): GraphRequest;
     skip(n: number): GraphRequest;

src/GraphRequest.ts

@@ -127,17 +127,17 @@ export class GraphRequest {
      *     and .select("displayName", "birthday")
      * 
      */
-    select(properties:string|[string]):GraphRequest {
+    select(properties:string|string[]):GraphRequest {
         this.addCsvQueryParamater("$select", properties, arguments);
         return this;
     }
 
-    expand(properties:string|[string]):GraphRequest {
+    expand(properties:string|string[]):GraphRequest {
         this.addCsvQueryParamater("$expand", properties, arguments);
         return this;
     }
 
-    orderby(properties:string|[string]):GraphRequest {
+    orderby(properties:string|string[]):GraphRequest {
         this.addCsvQueryParamater("$orderby", properties, arguments);
         return this;
     }
@@ -174,7 +174,7 @@ export class GraphRequest {
     }
 
     // helper for $select, $expand and $orderby (must be comma separated)
-    private addCsvQueryParamater(propertyName:string, propertyValue:string|[string], additionalProperties:IArguments) {
+    private addCsvQueryParamater(propertyName:string, propertyValue:string|string[], additionalProperties:IArguments) {
         // if there are already $propertyName value there, append a ","
         this.urlComponents.oDataQueryParams[propertyName] = this.urlComponents.oDataQueryParams[propertyName] ? this.urlComponents.oDataQueryParams[propertyName] + "," : "";
 

tsconfig.json

@@ -7,6 +7,7 @@
     "removeComments": true,
     "sourceMap": true,
     "target": "es5",
+    "lib": ["es6", "dom"],
     "declaration": true,
     "outDir": "lib/"
   },