Add CodeSandbox configuration (#362)

* Add CodeSandbox configuration

* Update package.json

Author: ardatan

examples/javascript-cjs/package.json

@@ -4,6 +4,7 @@
   "version": "0.0.1",
   "scripts": {
     "start": "node index.js",
+    "prestart": "npm run build-client",
     "build-client": "graphclient build --fileType json",
     "graphiql": "graphclient serve-dev",
     "check": "exit 0"

examples/javascript-cjs/sandbox.config.json

@@ -0,0 +1,7 @@
+{
+  "template": "node",
+  "container": {
+    "node": "16",
+    "port": 4000
+  }
+}