Add invalidate endpoint

Author: camertron

lib/Server.js

@@ -299,6 +299,11 @@ class Server {
       res.end('</body></html>');
     });
 
+    app.get('/invalidate', (_req, res) => {
+      this.invalidate();
+      res.end();
+    });
+
     let contentBase;
 
     if (options.contentBase !== undefined) {

test/Routes.test.js

@@ -33,6 +33,10 @@ describe('Routes', () => {
       .expect(200, done);
   });
 
+  it('GET request to invalidate endpoint', (done) => {
+    req.get('/invalidate').expect(200, done);
+  });
+
   it('GET request to live bundle', (done) => {
     req
       .get('/__webpack_dev_server__/live.bundle.js')