Add strict types

index.js

@@ -1,8 +1,10 @@
 /**
  * Parse space separated tokens to an array of strings.
  *
- * @param {string} value Space separated tokens
- * @returns {Array.<string>} Tokens
+ * @param {string} value
+ *   Space separated tokens.
+ * @returns {Array<string>}
+ *   Tokens.
  */
 export function parse(value) {
   const input = String(value || '').trim()
@@ -12,8 +14,10 @@ export function parse(value) {
 /**
  * Serialize an array of strings as space separated tokens.
  *
- * @param {Array.<string|number>} values Tokens
- * @returns {string} Space separated tokens
+ * @param {Array<string|number>} values
+ *   Tokens.
+ * @returns {string}
+ *   Space separated tokens.
  */
 export function stringify(values) {
   return values.join(' ').trim()

tsconfig.json

@@ -1,16 +1,17 @@
 {
-  "files": ["index.js"],
-  "include": ["*.js"],
+  "include": ["**/**.js"],
+  "exclude": ["coverage", "node_modules"],
   "compilerOptions": {
-    "target": "ES2020",
-    "lib": ["ES2020"],
-    "module": "ES2020",
-    "moduleResolution": "node",
-    "allowJs": true,
     "checkJs": true,
     "declaration": true,
     "emitDeclarationOnly": true,
-    "allowSyntheticDefaultImports": true,
-    "skipLibCheck": true
+    "exactOptionalPropertyTypes": true,
+    "forceConsistentCasingInFileNames": true,
+    "lib": ["es2020"],
+    "module": "node16",
+    "newLine": "lf",
+    "skipLibCheck": true,
+    "strict": true,
+    "target": "es2020"
   }
 }