Installed ESLint with recommended config for node

Installed ESLint and then used init to set it up. I had it use the
recommended settings, environment for node.
Fixes: nodejs#310

.eslintrc.js

@@ -0,0 +1,17 @@
+module.exports = {
+    "env": {
+        "node": true,
+        "commonjs": true,
+        "es6": true
+    },
+    "extends": ["eslint:recommended"],
+    "globals": {
+        "Atomics": "readonly",
+        "SharedArrayBuffer": "readonly"
+    },
+    "parserOptions": {
+        "ecmaVersion": 2018
+    },
+    "rules": {
+    }
+};

package.json

@@ -26,7 +26,8 @@
     "codecov-upload-js": "codecov --disable=gcov --file=coverage-js.lcov",
     "codecov-upload": "npm run codecov-upload-cc && npm run codecov-upload-js",
     "linter": "node scripts/linter.js",
-    "format": "npx clang-format -i src/*"
+    "format": "npx clang-format -i src/*",
+    "lint-test": "(npx eslint test{,/**}/*.js && echo 'No problems found') || echo 'Lint failed for some files'"
   },
   "repository": {
     "type": "git",
@@ -54,9 +55,10 @@
   },
   "homepage": "https://github.com/nodejs/llnode#readme",
   "devDependencies": {
+    "clang-format": "1.2.4",
     "codecov": "^3.1.0",
+    "eslint": "^6.5.1",
     "nyc": "^13.1.0",
-    "clang-format": "1.2.4",
     "tape": "^4.4.0"
   },
   "nyc": {
@@ -73,4 +75,4 @@
     "bindings": "^1.3.0",
     "node-addon-api": "^1.1.0"
   }
-}
+}