Add strict to tsconfig.json

Author: wooorm

index.js

@@ -48,6 +48,7 @@ function walk(node, state) {
   for (key in node) {
     if (own.call(node, key)) {
       /** @type {EstreeNode|EstreeNode[]} */
+      // @ts-expect-error: indexable.
       const value = node[key]
 
       // Ignore comments.

tsconfig.json

@@ -11,6 +11,7 @@
     "declaration": true,
     "emitDeclarationOnly": true,
     "allowSyntheticDefaultImports": true,
-    "skipLibCheck": true
+    "skipLibCheck": true,
+    "strict": true
   }
 }