Convert to use typescript, implement eslint

tsconfig.json

@@ -0,0 +1,22 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "commonjs",
+    "outDir": "build",
+    "rootDir": "src",
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+    "resolveJsonModule": true,
+    "sourceMap": true,
+    "declaration": false,
+    "lib": ["ES2022", "DOM"],
+    "types": ["node"],
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "noFallthroughCasesInSwitch": true,
+    "noImplicitReturns": true
+  },
+  "include": ["src/**/*.ts"]
+}