Microsoft/TypeScript

Ternary operator breaks syntax highlighting in tsx file

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#56,696 opened on Dec 6, 2023

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BugDomain: JSX/TSXHelp Wanted

Description

Does this issue occur when all extensions are disabled?: Yes

  • VS Code Version: 1.84.2
  • OS Version: Windows 11 build 22621

Steps to Reproduce:

  1. Create a .tsx file
  2. Paste this code
import { useState } from "react"
import './OS.css'
import Window from './Window'

const OS = () => {
    const [loaded, setLoaded] = useState(false);

    return (
        loaded ?
            <div id="OS">

            </div>
            :
            <div id="loading">
                <Window title="Starting Up">

                </Window>
            </div>
    )
}

export default OS

All editor features will be broken in the second half of the ternary operator. No tag closing, no indentation, and syntax highlighting is funky image

Contributor guide

Tech stack
typescriptreact
Domain
developer experience
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
4
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.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
TypeScript language service internalsJSX parsing
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
Investigate the TypeScript language service's syntax highlighting logic for JSX elements inside ternary expressions. The bug indicates that the tokenizer or semantic token provider incorrectly handles the alternate branch of a ternary when it contains JSX. Look at files like src/services/syntaxHighlighter.ts or src/compiler/scanner.ts. Check if any recent changes to JSX parsing or ternary handling could have introduced this issue.