add eslint + prettier

.editorconfig

@@ -0,0 +1,12 @@
+root = true
+
+[*]
+indent_style = space
+indent_size = 2
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
+
+[*.md]
+trim_trailing_whitespace = false

.eslintignore

@@ -0,0 +1,2 @@
+node_modules
+__tests__/fixtures/

.eslintrc.js

@@ -0,0 +1,71 @@
+const OFF = 0;
+const WARN = 1;
+const ERROR = 2;
+
+module.exports = {
+  parser: 'babel-eslint',
+  parserOptions: {
+    ecmaVersion: 7,
+    sourceType: 'module',
+    ecmaFeatures: {
+      jsx: false,
+      experimentalObjectRestSpread: true,
+    },
+  },
+  root: true, // stop ESLint from looking for a configuration file in parent folders
+  env: {
+    es6: true,
+    jest: true,
+    node: true,
+  },
+
+  extends: ['@kiwicom/eslint-config'],
+
+  rules: {
+    'no-process-env': ERROR,
+    'no-restricted-imports': [
+      ERROR,
+      {
+        paths: [
+          {
+            name: 'graphql-relay',
+            // TODO: eventually just disallow it completely
+            importNames: [
+              'fromGlobalId', // @kiwicom/graphql-global-id
+              'toGlobalId',
+              'connectionArgs', // @kiwicom/graphql-utils
+              'connectionDefinitions',
+              'connectionFromArray',
+              'connectionFromArraySlice',
+              'connectionFromPromisedArray',
+              'connectionFromPromisedArraySlice',
+            ],
+          },
+        ],
+      },
+    ],
+    'import/no-extraneous-dependencies': [
+      ERROR,
+      {
+        devDependencies: ['/scripts/**', '**/*.test.js', '**/*.spec.js'],
+      },
+    ],
+    'dependencies/no-cycles': OFF, // cycles are sometimes expected in GraphQL
+
+    // Possible future of @kiwicom/eslint-config:
+    'jest/prefer-to-be-null': ERROR,
+    'jest/prefer-to-be-undefined': ERROR,
+    'jest/prefer-to-contain': ERROR,
+    'jest/prefer-to-have-length': ERROR,
+  },
+
+  overrides: [
+    {
+      files: ['scripts/**/*.js', 'src/packages/**/*.js'],
+      rules: {
+        // It's expected to access process.env in our NPM packages or scrips.
+        'no-process-env': OFF,
+      },
+    },
+  ],
+};

jest-eslint.config.js

@@ -0,0 +1,9 @@
+// @flow
+
+module.exports = {
+  displayName: 'lint',
+  verbose: false,
+  reporters: ['default'],
+  runner: './src/packages/eslint-config-kiwicom/eslint-runner/index.js',
+  testMatch: ['<rootDir>/src/**/*.js', '<rootDir>/scripts/**/*.js'],
+};

package.json

@@ -2,12 +2,20 @@
   "name": "osmcz-v2",
   "scripts": {
     "dev": "next ./src",
+    "lint": "eslint --print-config . | eslint-config-prettier-check && eslint . --report-unused-disable-directives",
     "build": "next build ./src",
     "start": "next start ./src"
   },
   "dependencies": {
     "next": "^7.0.2",
     "react": "^16.7.0",
     "react-dom": "^16.7.0"
+  },
+  "devDependencies": {
+    "@kiwicom/eslint-config": "^2.1.0",
+    "eslint": "^5.12.1",
+    "eslint-plugin-jsx-a11y": "^6.1.2",
+    "babel-plugin-styled-components": "^1.10.0",
+    "babel-eslint": "^10.0.1"
   }
 }

src/next.config.js

@@ -1,10 +1,12 @@
+// @flow
+
 module.exports = {
   webpack: config => {
     // Fixes npm packages that depend on `fs` module
     config.node = {
-      fs: 'empty'
-    }
+      fs: 'empty',
+    };
 
-    return config
-  }
-}
+    return config;
+  },
+};

src/pages/index.js

@@ -1,8 +1,7 @@
-import React from 'react'
+// @flow
 
-const Home = () => (
-  <div>
-  </div>
-)
+import React from 'react';
 
-export default Home
+const Home = () => <div />;
+
+export default Home;