Use eslint+prettier

Author: saschanaz

.eslintrc.cjs

@@ -0,0 +1,20 @@
+module.exports = {
+  root: true,
+  env: {
+    node: true,
+    browser: true,
+  },
+  parser: "@typescript-eslint/parser",
+  plugins: ["@typescript-eslint"],
+  extends: [
+    "eslint:recommended",
+    "plugin:@typescript-eslint/recommended",
+    "plugin:prettier/recommended",
+  ],
+  rules: {
+    "no-prototype-builtins": 0,
+    "@typescript-eslint/no-explicit-any": 0,
+    "@typescript-eslint/no-non-null-assertion": 0,
+    "@typescript-eslint/no-var-requires": 0,
+  },
+};

package.json

@@ -10,7 +10,8 @@
     "fetch-mdn": "npm run build && node ./lib/mdnfetcher.js",
     "fetch": "echo This could take a few minutes... && npm run fetch-idl && npm run fetch-mdn",
     "baseline-accept": "cpx \"generated\\*\" baselines\\",
-    "test": "tsc -p ./tsconfig.json && node ./lib/index.js && node ./lib/test.js",
+    "lint": "eslint --max-warnings 0 src",
+    "test": "npm run lint && npm run build && node ./lib/test.js",
     "danger": "danger",
     "migrate": "node ./lib/migrate-to-tsc.js"
   },
@@ -20,14 +21,20 @@
     "@types/node": "^14.6.4",
     "@types/node-fetch": "^2.5.7",
     "@types/webidl2": "^23.13.2",
+    "@typescript-eslint/eslint-plugin": "^4.16.1",
+    "@typescript-eslint/parser": "^4.16.1",
     "cpx2": "^2.0.0",
     "danger": "^10.5.4",
+    "eslint": "^7.21.0",
+    "eslint-config-prettier": "^8.1.0",
+    "eslint-plugin-prettier": "^3.3.1",
     "jsdom": "^16.4.0",
     "node-fetch": "^2.6.1",
     "parse-diff": "^0.7.0",
+    "prettier": "^2.2.1",
     "print-diff": "^1.0.0",
     "styleless-innertext": "^1.1.2",
-    "typescript": "4.1.0-dev.20200908",
+    "typescript": "^4.2.3",
     "webidl2": "^23.13.0"
   }
 }