Fix problem with MultiCompiler in v4 (#88)

* add failing test for MultiCompiler

* fix #87 - no failed hook on MultiCompiler

* modify code semantics to maintainer preference

* maintainer is a dummy and left an extra semicolon

Author: mike-marcacci

index.js

@@ -21,9 +21,19 @@ function koaDevware(dev, compiler) {
         resolve(true);
       });
 
-      compiler.hooks.failed.tap('KoaWebpack', (error) => {
-        reject(error);
-      });
+      function tapFailedHook(comp) {
+        comp.hooks.failed.tap('KoaWebpack', (error) => {
+          reject(error);
+        });
+      }
+
+      if (compiler.compilers) {
+        for (const child of compiler.compilers) {
+          tapFailedHook(child);
+        }
+      } else {
+        tapFailedHook(compiler);
+      }
     });
   }
 

test/results.js

@@ -90,6 +90,42 @@ describe('koa-webpack', () => {
       });
   }).timeout(5e3);
 
+  it('sends the result to a MultiCompiler in watch mode', (done) => {
+    const { middleware, req, server } = setup({
+      dev: { lazy: false },
+      config: [
+        {
+          entry: [path.resolve(__dirname, 'fixtures', 'input.js')],
+          output: {
+            path: path.resolve(__dirname, 'fixtures'),
+            filename: 'output.js'
+          }
+        },
+        {
+          entry: [path.resolve(__dirname, 'fixtures', 'input.js')],
+          output: {
+            path: path.resolve(__dirname, 'fixtures'),
+            filename: 'output2.js'
+          }
+        }
+      ]
+    });
+    req.get('/output.js')
+      .expect(200)
+      .expect((response) => {
+        assert.ok(/Hello world/.test(response.text), "Expected result to contain 'Hello world'");
+      })
+      .then(() => req.get('/output2.js')
+        .expect(200)
+        .expect((response) => {
+          assert.ok(/Hello world/.test(response.text), "Expected result to contain 'Hello world'");
+        })
+        .then(() => {
+          server.kill();
+          middleware.close(done);
+        }));
+  }).timeout(5e3);
+
   it('builds and sends the result in lazy mode', (done) => {
     const { middleware, req, server } = setup({ dev: { lazy: true } });
     req.get('/output.js')