wip. refactor

Author: GoodDayForSurf

packages/devextreme-cli/testing/dev-server.js

@@ -7,7 +7,12 @@ const runCommand = require('../src/utility/run-command');
 const { themes, swatchModes, baseFontFamily } = require('./constants');
 
 class nextJsState {
-    async start(env) {
+    constructor(env) {
+        this.proc = null;
+        this.env = env;
+    }
+
+    async start() {
         this.proc = runCommand('npm', ['run', 'start'], {
             cwd: this.env.appPath,
             noExit: true,