TypeScript Monorepo Demo

This repository demonstrates a limitation in TypeScript's "Go to Definition" functionality when working with nested package imports in a monorepo. While upcoming improvements in TypeScript (PR #60005) have partially addressed this issue, some limitations still remain with deeply nested property access.

Setup Instructions

git clone [email protected]:KATT/typescript-go-to-definition-through-sub-packages.git
cd typescript-go-to-definition-through-sub-packages
pnpm i

& if you want to watch for changes:

pnpm dev

Problem Explanation

TypeScript's "Go to Definition" does not work through multiple levels of package imports. Here's the setup:

1. Package @org/a defines a base object:

   export const a = {
   	foo: 'foo',
   	bar: 'bar',
   	baz: 'baz',
   	qux: 'qux',
   } as const;

2. Package @org/b imports and re-exports package @org/a's object:

   import { a } from '@org/a';
   
   a; // ✅ Go to definition works here with ^5.7.3
   a.foo; // 🚧 Go to definition does not work here, but seemingly fixed by https://github.com/microsoft/TypeScript/pull/60005
   // ^?
   
   export const b = {
   	a,
   } as const;

3. Package @org/c imports from package @org/b and tries to access the nested property:

   import { b } from '@org/b';
   
   b; // 🚧 Go to definition does not work here, but seemingly fixed by https://github.com/microsoft/TypeScript/pull/60005
   b.a; // <--- 🚧 Go to definition does not work here, but seemingly fixed by https://github.com/microsoft/TypeScript/pull/60005
   b.a.foo; // <--- ❌ Go to definition on ".foo" should go to `a.foo` in `@org/a`, but instead goes to end of file in `@org/b`

Expected Behavior

Go to definition should work through multiple levels of package imports as if the code was written in a single file.

Current Behavior

• In package @org/b, TypeScript's "Go to Definition" works as expected when clicking on a.foo
• In package @org/c, "Go to Definition" does not work as expected when trying to navigate through the re-exported property b.a.foo

Technical Details

All packages:

• Use TypeScript with strict configuration
• Are properly linked using workspace:* dependencies
• Generate declaration maps (enabled in base tsconfig)