Add strict to tsconfig.json

Author: wooorm

package.json

@@ -69,10 +69,7 @@
     "trailingComma": "none"
   },
   "xo": {
-    "prettier": true,
-    "rules": {
-      "capitalized-comments": "off"
-    }
+    "prettier": true
   },
   "remarkConfig": {
     "plugins": [

test.js

@@ -57,8 +57,11 @@ test('mdast-util-definitions', (t) => {
     'should work on weird identifiers'
   )
 
-  /* eslint-disable-next-line no-use-extend-native/no-use-extend-native */
-  t.equal({}.type, undefined, 'should not polute the prototype') // type-coverage:ignore-line
+  /* eslint-disable no-use-extend-native/no-use-extend-native */
+  // @ts-expect-error: yes.
+  // type-coverage:ignore-next-line
+  t.equal({}.type, undefined, 'should not polute the prototype')
+  /* eslint-enable no-use-extend-native/no-use-extend-native */
 
   t.deepEqual(
     definitions(tree)('toString'),
@@ -70,8 +73,10 @@ test('mdast-util-definitions', (t) => {
     '[example]: https://one.com\n[example]: https://two.com'
   )
 
+  const example = definitions(tree)('example')
+
   t.deepEqual(
-    definitions(tree)('example').url,
+    example && example.url,
     'https://one.com',
     'should prefer the first of duplicate definitions'
   )

tsconfig.json

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