Microsoft/TypeScript

Omitting a property from tuple breaks destruction

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#54,371 opened on May 24, 2023

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 (17 comments) (0 reactions) (0 assignees)TypeScript (6,726 forks)batch import
BugDomain: Mapped TypesHelp Wanted

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Description

Bug Report

🔎 Search Terms

tuple omit property Searched in Bing and Github issues but I found nothing

🕗 Version & Regression Information

  • This is the behavior in every version I tried

⏯ Playground Link

Link

💻 Code

const foo = [1, "2"] as const
const [a, b] = foo // everything works well, a is number and b is string

const bar = [1, "2"] as Omit<[number, string], "at">
const [c, d] = bar // Oops! c and d are string | number now

🙁 Actual behavior

↑ c and d are both string | number

🙂 Expected behavior

a and b should have correct type

Contributor guide

Research direction
Investigate the TypeScript type checker's handling of tuple types when using Omit and destructuring. Focus on the subtype checking logic for tuples with rest elements and the Omit utility type.
Tech stack
typescript
Domain
backend
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
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.
40