[babel__traverse] Return correct type in get() when Array is nullable (…

…DefinitelyTyped#59788) * fix(babel__traverse): Return correct type in get() when Array is nullable * fix: Fix return type
andyGallagher · Apr 26, 2022 · 667cea3 · 667cea3
1 parent de71f8e
commit 667cea3
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diff --git a/types/babel__traverse/babel__traverse-tests.ts b/types/babel__traverse/babel__traverse-tests.ts
@@ -350,6 +350,13 @@ const visitorWithInvalidDenylist: Visitor = {
     denylist: ['SomeRandomType'],
 };
 
+const objectTypeAnnotation: NodePath<t.ObjectTypeAnnotation> = new NodePath<t.ObjectTypeAnnotation>(
+    null as any,
+    {} as any,
+);
+
+objectTypeAnnotation.get('indexers'); // $ExpectType NodePath<null | undefined> | NodePath<ObjectTypeIndexer>[]
+
 // Test that NodePath can be narrowed from union to single type
 const path: NodePath<t.ExportDefaultDeclaration | t.ExportNamedDeclaration> = new NodePath<t.ExportNamedDeclaration>(
     null as any,

diff --git a/types/babel__traverse/index.d.ts b/types/babel__traverse/index.d.ts
@@ -553,6 +553,8 @@ export class NodePath<T = Node> {
         context?: boolean | TraversalContext,
     ): T[K] extends Array<Node | null | undefined>
         ? Array<NodePath<T[K][number]>>
+        : T[K] extends Array<Node | null | undefined> | null | undefined
+        ? Array<NodePath<NonNullable<T[K]>[number]>> | NodePath<null | undefined>
         : T[K] extends Node | null | undefined
         ? NodePath<T[K]>
         : never;