Introduce ESLint and Prettier with standardized configurations

Author: nathanieliov

.gitignore

@@ -18,3 +18,4 @@ tcpsigner.log
 logs/
 federate-node.jar
 zlogs/
+.eslintcache

.prettierignore

@@ -0,0 +1,23 @@
+# Dependency Directories
+node_modules/
+
+# Build Outputs
+dist/
+build/
+coverage/
+
+# Auto-generated artifacts
+package-lock.json
+pnpm-lock.yaml
+
+# OS / Editor junk
+.DS_Store
+.idea/
+.vscode/
+
+# File types to ignore
+*.json
+*.xml
+*.md
+*.yml
+*.yaml

.prettierrc.json

@@ -0,0 +1,11 @@
+{
+  "semi": true,
+  "trailingComma": "es5",
+  "singleQuote": true,
+  "printWidth": 100,
+  "tabWidth": 4,
+  "useTabs": false,
+  "arrowParens": "always",
+  "endOfLine": "lf",
+  "bracketSpacing": true
+}

eslint.config.cjs

@@ -0,0 +1,37 @@
+const js = require('@eslint/js');
+const globals = require('globals');
+const prettierRecommended = require('eslint-plugin-prettier/recommended');
+
+const JS_FILES = ['**/*.js']; // only .js files (not .mjs/.cjs)
+
+module.exports = [
+    // Optional global ignores
+    { ignores: ['node_modules/**', 'dist/**', 'coverage/**'] },
+
+    // Apply everything below only to .js files
+    { files: JS_FILES },
+
+    // Equivalent of "extends: ['eslint:recommended']"
+    js.configs.recommended,
+
+    // Your environment + language options
+    {
+        files: JS_FILES,
+        languageOptions: {
+            ecmaVersion: 2021,
+            sourceType: 'module',
+            globals: {
+                ...globals.node,
+                ...globals.es2021,
+                ...globals.mocha,
+            },
+        },
+        rules: {
+            'no-console': 'warn',
+            'prettier/prettier': 'error',
+        },
+    },
+
+    // Equivalent of "plugin:prettier/recommended" (keep last)
+    prettierRecommended,
+];