[tests] add editorconfig and eslint

.editorconfig

@@ -0,0 +1,11 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+indent_size = 2
+indent_style = space
+insert_final_newline = true
+max_line_length = 120
+tab_width = 4
+trim_trailing_whitespace = true

.eslintrc.js

@@ -0,0 +1,25 @@
+module.exports = {
+  env: {
+    commonjs: true,
+    es6: true,
+    node: true
+  },
+  extends: [
+    'airbnb-base'
+  ],
+  globals: {
+    Atomics: 'readonly',
+    SharedArrayBuffer: 'readonly'
+  },
+  parserOptions: {
+    ecmaVersion: 2018,
+  },
+  rules: {
+    "comma-dangle": [
+      "error",
+      "never"
+    ],
+    "no-console": "off",
+    "object-curly-newline": "off"
+  }
+};

.gitignore

@@ -17,3 +17,5 @@ node_modules/
 .env
 .env.test
 
+# Ide
+.idea

package.json

@@ -9,10 +9,14 @@
     "rsyncwrapper": "3.0.1"
   },
   "devDependencies": {
-    "@zeit/ncc": "^0.20.5"
+    "@zeit/ncc": "^0.20.5",
+    "eslint": "^6.8.0",
+    "eslint-config-airbnb-base": "^14.1.0",
+    "eslint-plugin-import": "^2.20.2"
   },
   "scripts": {
-    "build": "ncc build ./src/index.js -o dist"
+    "build": "npm run lint && ncc build ./src/index.js -o dist",
+    "lint": "eslint ./src/index.js"
   },
   "repository": {
     "type": "git",