Microsoft/TypeScript

Error when accessing properties on `globalThis` with the same name of a global variable

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#58,345 opened on Apr 28, 2024

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 (5 comments) (1 reaction) (0 assignees)TypeScript (6,726 forks)batch import
BugDomain: Something ElseHelp Wanted

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Description

🔎 Search Terms

globalThis redefined error script property does not exist

🕗 Version & Regression Information

  • This is the behavior in every version I tried

⏯ Playground Link

https://www.typescriptlang.org/play/?noImplicitAny=false&ts=5.5.0-beta#code/DYUwLgBAlgdgbgQ2FAJgRggXggc2AewCMkAVACygGcA6WRZdAbgChRIBPLXA44cq2vCSo0LNhABeXPEVIUadYSgBMLIA

💻 Code

let invalid1 = globalThis.invalid1;
let y = globalThis.invalid1;
let z = globalThis.invalid2;

🙁 Actual behavior

Property 'invalid1' does not exist on type 'typeof globalThis'.

🙂 Expected behavior

It should either complain about both invalid1 and invalid2, or neither

Additional information about the issue

It only happens in scripts and not in modules (if I add export {}, there are no reported errors).

Contributor guide

Research direction
Investigate the TypeScript type checker's handling of globalThis property access in script mode vs module mode. Look at how the compiler determines when a property name shadows a global variable declaration and why it only reports an error for the first access of that property name.
Tech stack
typescript
Domain
tooling
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
Half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
TypeScriptGit
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60