setup eslint

Author: DaniAkash

.eslintrc.js

@@ -0,0 +1,22 @@
+module.exports = {
+  parser: "@typescript-eslint/parser",
+  plugins: ["tsc", "jest"],
+  root: true,
+  extends: "@react-native-community",
+  rules: {
+    quotes: ["warn", "double", { allowTemplateLiterals: true }],
+    "tsc/config": [
+      1,
+      {
+        configFile: "tsconfig.json"
+      }
+    ],
+    "comma-dangle": 0,
+    "react/prop-types": 1,
+    "prettier/prettier": 1,
+    "@typescript-eslint/no-unused-vars": 1
+  },
+  env: {
+    "jest/globals": true
+  }
+};

package.json

@@ -18,11 +18,15 @@
     "masonry-scroll"
   ],
   "devDependencies": {
+    "@react-native-community/eslint-config": "^0.0.7",
     "@testing-library/react-native": "^5.0.3",
     "@types/jest": "^25.1.1",
     "@types/react": "^16.9.19",
     "@types/react-native": "^0.61.7",
     "@types/react-test-renderer": "^16.9.2",
+    "eslint": "^6.8.0",
+    "eslint-plugin-prettier": "^3.1.2",
+    "eslint-plugin-tsc": "^1.2.0",
     "husky": "^4.2.1",
     "jest": "^25.1.0",
     "metro-react-native-babel-preset": "^0.58.0",

precommit-lint.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+
+echo "ESLint running for staged files..."
+
+# from https://eslint.org/docs/user-guide/integrations#source-control - Git pre-commit hook that only lints staged changes
+for file in $(git diff --cached --name-only | grep -E '\.(js|jsx|ts|tsx)$')
+do
+  git show ":$file" | node_modules/.bin/eslint --stdin --stdin-filename "$file" --max-warnings 0 # we only want to lint the staged changes, not any un-staged changes
+  if [ $? -ne 0 ]; then
+    echo "ESLint failed on staged file '$file'. Please check your code and try again. You can run ESLint manually via npm run eslint."
+    exit 1 # exit with failure status
+  fi
+done