Added .eslintrc.json

.eslintrc.json

@@ -0,0 +1,25 @@
+{
+    "env": {
+        "browser": true,
+        "commonjs": true,
+        "es6": true,
+        "webextensions": true
+    },
+    "parserOptions": {
+        "ecmaFeatures": {
+            "jsx": true
+        },
+        "sourceType": "script"
+    },
+    "rules": {
+        "no-const-assign": "warn",
+        "no-this-before-super": "warn",
+        "no-undef": "warn",
+        "no-unreachable": "warn",
+        "no-unused-vars": "warn",
+        "constructor-super": "warn",
+        "valid-typeof": "warn",
+        "brace-style": "warn",
+        "strict": "warn"
+    }
+}