Make aspnet-webpack resilient against Webpack configs with nonstring entrypoints. Fixes aspnet#376.

Author: SteveSandersonMS

src/Microsoft.AspNetCore.SpaServices/npm/aspnet-webpack/package.json

@@ -1,6 +1,6 @@
 {
   "name": "aspnet-webpack",
-  "version": "1.0.20",
+  "version": "1.0.21",
   "description": "Helpers for using Webpack in ASP.NET Core projects. Works in conjunction with the Microsoft.AspNetCore.SpaServices NuGet package.",
   "main": "index.js",
   "scripts": {

src/Microsoft.AspNetCore.SpaServices/npm/aspnet-webpack/src/WebpackDevMiddleware.ts

@@ -231,7 +231,7 @@ function getPath(publicPath: string) {
 function firstIndexOfStringStartingWith(array: string[], prefixToFind: string) {
     for (let index = 0; index < array.length; index++) {
         const candidate = array[index];
-        if (candidate.substring(0, prefixToFind.length) === prefixToFind) {
+        if ((typeof candidate === 'string') && (candidate.substring(0, prefixToFind.length) === prefixToFind)) {
             return index;
         }
     }