:recycle: added linting and formatting | added test config

.gitignore

+.vscode
 node_modules
+coverage

package.json

     "description": "liquid measurement",
     "main": "index.js",
     "scripts": {
-        "test": "echo \"Error: no test specified\" && exit 1"
+        "test": "vitest run --coverage"
     },
     "type": "module",
     "author": "TOJ",
         "nanoid": "^3.3.7"
     },
     "devDependencies": {
+        "@vitest/coverage-v8": "^1.4.0",
+        "oxlint": "^0.2.14",
         "vitest": "^1.3.1"
+    },
+    "prettier": {
+        "trailingComma": "all",
+        "tabWidth": 4,
+        "semi": false,
+        "singleQuote": true,
+        "bracketSpacing": true,
+        "arrowParens": "avoid"
     }
 }

vitest.config.ts

+import { defineConfig } from 'vitest/config'
+
+export default defineConfig({
+    test: {
+        coverage: {
+            provider: 'v8', // or 'v8'
+        },
+    },
+})