🤖 Merge PR DefinitelyTyped#72228 [@babel/traverse]: Add support for recursive NodePath::get(…) calls by @ExE-Boss

Author: ExE-Boss

types/babel__traverse/babel__traverse-tests.ts

@@ -25,6 +25,7 @@ const MyVisitor2: Visitor = {
     },
     ArrayExpression(path) {
         path.get("elements"); // $ExpectType NodePath<SpreadElement | Expression | null>[]
+        path.get("elements.0"); // $ExpectType NodePath<SpreadElement | Expression | null>
     },
     Program(path) {
         path.parentPath; // $ExpectType null
@@ -374,6 +375,7 @@ const objectTypeAnnotation: NodePath<t.ObjectTypeAnnotation> = new NodePath<t.Ob
 );
 
 objectTypeAnnotation.get("indexers"); // $ExpectType NodePathResult<ObjectTypeIndexer[] | undefined>
+objectTypeAnnotation.get("indexers.0"); // $ExpectType NodePath<ObjectTypeIndexer>
 
 // Test that NodePath can be narrowed from union to single type
 const path: NodePath<t.ExportDefaultDeclaration | t.ExportNamedDeclaration> = new NodePath<t.ExportNamedDeclaration>(
@@ -427,7 +429,9 @@ binding.deopValue();
 binding.clearValue();
 
 binding.reassign(newPath.get("body")[0]);
+binding.reassign(newPath.get("body.0"));
 binding.reference(newPath.get("body")[0]);
+binding.reference(newPath.get("body.0"));
 binding.dereference();
 
 newPath.scope.checkBlockScopedCollisions(binding, "local", "name", {});

types/babel__traverse/index.d.ts

@@ -746,6 +746,7 @@ export class NodePath<T = Node> {
     getAllNextSiblings(): NodePath[];
 
     get<K extends keyof T>(key: K, context?: boolean | TraversalContext): NodePathResult<T[K]>;
+    get<P extends string>(path: P, context?: boolean | TraversalContext): NodePathResult<ImplGetRecursive<T, P>>;
     get(key: string, context?: boolean | TraversalContext): NodePath | NodePath[];
 
     getBindingIdentifiers(duplicates: true): Record<string, t.Identifier[]>;
@@ -1448,6 +1449,27 @@ export interface TraversalContext<S = unknown> {
     opts: TraverseOptions;
 }
 
+// Based on `GetFieldType`s from `@types/lodash/common/object.d.ts`:
+// dprint-ignore
+type ImplGetOfArray<T extends readonly unknown[], K extends string> =
+    K extends `${infer N extends number}` ? T[N]
+    : K extends keyof T ? T[K]
+    : never;
+
+// dprint-ignore
+type ImplGetByKey<T, K extends string>
+    = T extends readonly unknown[] ? ImplGetOfArray<T, K>
+    : K extends keyof T ? T[K]
+    : K extends `${infer N extends number}`
+        ? N extends keyof T ? T[N] : never
+    : never;
+
+// dprint-ignore
+type ImplGetRecursive<T, K extends string>
+    = K extends `${infer L}.${infer R}`
+        ? ImplGetRecursive<ImplGetByKey<T, L>, R>
+    : ImplGetByKey<T, K>;
+
 export type NodePathResult<T> =
     | (Extract<T, Node | null | undefined> extends never ? never : NodePath<Extract<T, Node | null | undefined>>)
     | (T extends Array<Node | null | undefined> ? Array<NodePath<T[number]>> : never);