Add strict to tsconfig.json

Author: wooorm

Diff for: test.js

@@ -162,10 +162,10 @@ test('unist-util-find-all-before', (t) => {
 
   /**
    * @param {unknown} _
-   * @param {number} n
+   * @param {number|null|undefined} n
    */
   function test(_, n) {
-    return n > 3
+    return typeof n === 'number' && n > 3
   }
 
   t.end()

Diff for: tsconfig.json

@@ -10,6 +10,7 @@
     "declaration": true,
     "emitDeclarationOnly": true,
     "allowSyntheticDefaultImports": true,
-    "skipLibCheck": true
+    "skipLibCheck": true,
+    "strict": true
   }
 }