feat(karma-esm): use file watcher for reloading karma

packages/karma-esm/package.json

@@ -34,6 +34,7 @@
     "es-dev-server": "^1.14.2",
     "minimatch": "^3.0.4",
     "portfinder": "^1.0.21",
+    "chokidar": "^3.0.2",
     "request": "^2.88.0"
   },
   "devDependencies": {

packages/karma-esm/src/esm-middleware.js

@@ -2,7 +2,8 @@
 const request = require('request');
 const minimatch = require('minimatch');
 const portfinder = require('portfinder');
-const { startServer, createConfig, messageChannelEndpoint } = require('es-dev-server');
+const chokidar = require('chokidar');
+const { startServer, createConfig } = require('es-dev-server');
 const { createEsmConfig } = require('./esm-config.js');
 
 async function setupDevServer(karmaConfig, esmConfig, watch, babelConfig, karmaEmitter) {
@@ -28,14 +29,12 @@ async function setupDevServer(karmaConfig, esmConfig, watch, babelConfig, karmaE
     babelConfig,
   });
 
-  await startServer(esDevServerConfig);
+  const fileWatcher = chokidar.watch([]);
+  await startServer(esDevServerConfig, fileWatcher);
 
   if (watch) {
-    const messageChannel = request(`http://127.0.0.1:${devServerPort}${messageChannelEndpoint}`);
-    messageChannel.addListener('data', message => {
-      if (message.toString('utf-8').startsWith('event: file-changed')) {
-        karmaEmitter.refreshFiles();
-      }
+    fileWatcher.addListener('change', () => {
+      karmaEmitter.refreshFiles();
     });
   }
 

yarn.lock

@@ -1991,30 +1991,6 @@
   resolved "https://registry.yarnpkg.com/@open-wc/semantic-dom-diff/-/semantic-dom-diff-0.13.21.tgz#718b9ec5f9a98935fc775e577ad094ae8d8b7dea"
   integrity sha512-BONpjHcGX2zFa9mfnwBCLEmlDsOHzT+j6Qt1yfK3MzFXFtAykfzFjAgaxPetu0YbBlCfXuMlfxI4vlRGCGMvFg==
 
-"@open-wc/testing-karma-bs@file:./packages/testing-karma-bs":
-  version "1.1.48"
-  dependencies:
-    "@open-wc/testing-karma" "^3.1.23"
-    "@types/node" "^11.13.0"
-    karma-browserstack-launcher "^1.0.0"
-
-"@open-wc/testing-karma@file:./packages/testing-karma":
-  version "3.1.23"
-  dependencies:
-    "@open-wc/karma-esm" "^2.4.2"
-    axe-core "^3.3.1"
-    istanbul-instrumenter-loader "^3.0.0"
-    karma "^4.0.0"
-    karma-chrome-launcher "^2.0.0"
-    karma-coverage-istanbul-reporter "^2.0.0"
-    karma-mocha "^1.0.0"
-    karma-mocha-reporter "^2.0.0"
-    karma-mocha-snapshot "^0.2.1"
-    karma-snapshot "^0.6.0"
-    karma-source-map-support "^1.3.0"
-    karma-sourcemap-loader "^0.3.0"
-    mocha "^6.2.0"
-
 "@reach/router@^1.2.1":
   version "1.2.1"
   resolved "https://registry.yarnpkg.com/@reach/router/-/router-1.2.1.tgz#34ae3541a5ac44fa7796e5506a5d7274a162be4e"
@@ -5273,7 +5249,7 @@ chokidar@^2.0.0, chokidar@^2.0.2, chokidar@^2.0.3, chokidar@^2.0.4, chokidar@^2.
   optionalDependencies:
     fsevents "^1.2.7"
 
-chokidar@^3.0.0:
+chokidar@^3.0.0, chokidar@^3.0.2:
   version "3.0.2"
   resolved "https://registry.yarnpkg.com/chokidar/-/chokidar-3.0.2.tgz#0d1cd6d04eb2df0327446188cd13736a3367d681"
   integrity sha512-c4PR2egjNjI1um6bamCQ6bUNPDiyofNQruHvKgHQ4gDUP/ITSVSzNsiI5OWtHOsX323i5ha/kk4YmOZ1Ktg7KA==