added 'spa-asset-test' config option. Fixes #36

example/spa/.local-web-server.json

@@ -1,3 +1,4 @@
 {
-  "spa": "index.html"
+  "spa": "index.html",
+  "no-cache": true
 }

example/spa/index.html

@@ -7,6 +7,8 @@
   <li><a href="/login">/login</a></li>
   <li><a href="/search">/search</a></li>
 </ul>
+<p>Found asset: <img src="image.jpg" /></p>
+<p>Missing asset (should 404): <img src="sdafsadf.jpg" /></p>
 <script>
   document.querySelector('h2 span').textContent = window.location.pathname
 </script>

lib/middleware-stack.js

@@ -214,20 +214,23 @@ class MiddlewareStack extends Array {
   }
 
   /* for any URL not matched by static (e.g. `/search`), serve the SPA */
-  addSpa (spa) {
+  addSpa (spa, assetTest) {
     this.push({
       optionDefinitions: {
         name: 'spa', alias: 's', type: String, typeLabel: '[underline]{file}',
         description: 'Path to a Single Page App, e.g. app.html.'
       },
       middleware: function (cliOptions) {
-        spa = t.isDefined(cliOptions.spa) ? cliOptions.spa : spa
+        spa = cliOptions.spa || spa || 'index.html'
+        assetTest = new RegExp(cliOptions['spa-asset-test'] || assetTest || '\\.')
         if (spa) {
-          const historyApiFallback = require('koa-connect-history-api-fallback')
+          const send = require('koa-send')
+          const _ = require('koa-route')
           debug('SPA', spa)
-          return historyApiFallback({
-            index: spa,
-            verbose: cliOptions.verbose
+          return _.get('*', function spaMw (ctx, route, next) {
+            const root = path.resolve(cliOptions.directory || process.cwd())
+            debug(`SPA request. Route: ${route}, isAsset: ${assetTest.test(route)}`)
+            return send(ctx, assetTest.test(route) ? route : spa, { root: root }).then(next)
           })
         }
       }

package.json

@@ -40,7 +40,6 @@
     "koa-compose": "^3.1.0",
     "koa-compress": "^1.0.9",
     "koa-conditional-get": "^1.0.3",
-    "koa-connect-history-api-fallback": "~0.3.0",
     "koa-convert": "^1.2.0",
     "koa-etag": "^2.1.1",
     "koa-json": "^1.1.3",
@@ -53,7 +52,6 @@
     "path-to-regexp": "^1.5.0",
     "reduce-flatten": "^1.0.0",
     "stream-log-stats": "^1.1.3",
-    "string-tools": "^1.0.0",
     "test-value": "^2.0.0",
     "typical": "^2.4.2"
   },