THRIFT-5811: Update eslint & prettier

Client: js
Patch: Cameron Martin

This closes #3087

Author: cameron-martin

.eslintignore

@@ -0,0 +1,44 @@
+import globals from "globals";
+import js from "@eslint/js";
+import eslintPluginPrettierRecommended from "eslint-plugin-prettier/recommended";
+
+export default [
+  {
+    ignores: [
+      // TODO: Use eslint on js lib and generated code
+
+      // Ignore lib/js for now, which uses jshint currently
+      "lib/js/*",
+      // Ignore all generated code for now
+      "**/gen-*/",
+
+      // Don't lint nested node_modules
+      "**/node_modules/",
+    ],
+  },
+  js.configs.recommended,
+  eslintPluginPrettierRecommended,
+  {
+    languageOptions: {
+      globals: {
+        ...globals.node,
+      },
+
+      ecmaVersion: 2017,
+      sourceType: "commonjs",
+    },
+
+    rules: {
+      "no-console": "off",
+      "no-var": "error",
+      "prefer-const": "error",
+
+      "no-constant-condition": [
+        "error",
+        {
+          checkLoops: false,
+        },
+      ],
+    },
+  },
+];