introduce eslint

.eslintrc.js

@@ -0,0 +1,46 @@
+const config = {
+  extends: ['airbnb'],
+  parser: 'babel-eslint',
+  env: {
+    es6: true,
+  },
+  globals: {
+    document: true,
+    fetch: true,
+  },
+  settings: {
+    'import/resolver': {
+      'babel-module': {},
+    },
+  },
+  plugins: ['react', 'react-hooks'],
+  rules: {
+    'import/no-extraneous-dependencies': [
+      'error',
+      {
+        devDependencies: ['internals/**/*.js', 'client/**/stories.js'],
+      },
+    ],
+    'import/prefer-default-export': 0,
+    'no-else-return': 0,
+    'react/jsx-filename-extension': [1, { extensions: ['.js', '.jsx'] }],
+    'react/jsx-wrap-multilines': [
+      'error',
+      {
+        declaration: true,
+        assignment: true,
+        return: true,
+      },
+    ],
+    'react/no-unused-prop-types': 0,
+    'react/prefer-stateless-function': [0, { ignorePureComponents: true }],
+  },
+  parserOptions: {
+    ecmaFeatures: {
+      jsx: true,
+    },
+    sourceType: 'module',
+  },
+};
+
+module.exports = config;

package.json

@@ -5,11 +5,23 @@
   "scripts": {
     "dev": "next dev",
     "build": "next build",
-    "start": "next start"
+    "start": "next start",
+    "lint": "yarn run lint-eslint .",
+    "lint-eslint": "eslint --ignore-path .gitignore"
   },
   "dependencies": {
     "next": "9.0.3",
     "react": "16.9.0",
     "react-dom": "16.9.0"
+  },
+  "devDependencies": {
+    "babel-eslint": "~10.0.2",
+    "eslint": "~6.1.0",
+    "eslint-config-airbnb": "~18.0.1",
+    "eslint-import-resolver-babel-module": "~5.1.0",
+    "eslint-plugin-import": "~2.18.2",
+    "eslint-plugin-jsx-a11y": "~6.2.3",
+    "eslint-plugin-react": "~7.14.3",
+    "eslint-plugin-react-hooks": "~1.7.0"
   }
 }