Microsoft/TypeScript

TypeScript Language Features: `Analyzing '...' and its dependencies` takes crazy long time!

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#62,230 opened on Aug 7, 2025

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 (6 comments) (1 reaction) (0 assignees)TypeScript (48,455 stars) (6,726 forks)batch import
Domain: PerformanceHelp WantedPossible Improvement

Description

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

Version: 1.102.3 (user setup)
Commit: 488a1f239235055e34e673291fb8d8c810886f81
Date: 2025-07-29T03:00:23.339Z
Electron: 35.6.0
ElectronBuildId: 11847422
Chromium: 134.0.6998.205
Node.js: 22.15.1
V8: 13.4.114.21-electron.0
OS: Windows_NT x64 10.0.26100

This takes a long time for am empty TS file:

Steps to Reproduce:

  1. Install NodeJS.
  2. Create an empty folder. Open it with vsCode.
  3. Create the below files with the exact content shown.
  4. Run npm i in terminal to install packages.
  5. Open and view index.ts file.
  6. Do ctrl+shift+p and select TypeScript: Restart TS Server.
  7. In the Status Bar, you would see Analyzing 'index.ts' and its dependencies (Source: TypeScript and JavaScript Language Features).

The Analyzing 'index.ts' and its dependencies spins for a very long time. The package we installed, has a lot of files, but it wasn't like this before. Things worked fine with even a ton of packages and TS files.

Here are the source files to reproduce:

index.ts: EMPTY FILE!

package.json:

{
    "dependencies": {
        "phosphor-icons-svelte": "2.0.9"
    }
}

.gitignore:

/node_modules/

This issue may be related: https://github.com/microsoft/vscode/issues/244098

Locking issues should be a crime! I mentioned the issue and it's not visible in that issue page! I can't even comment on that issue page. Don't lock issues just because you don't like them. Locking issues breaks so many basic and necessary functionalities of GitHub.

Contributor guide

Tech stack
typescript
Domain
performancedeveloper experience
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.
3-5 days
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
Node.jsTypeScriptnpm
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
35
Research direction
Investigate why TypeScript's language service takes excessively long to analyze an empty file when 'phosphor icons svelte' is a dependency. The issue may be related to how the service traverses the entire dependency tree. Start by examining the TypeScript source code in 'src/services/' to understand how project language service initialization works. Profile the analysis to identify bottlenecks. Also review the linked issue #244098 for potential known causes. Consider adding caching or skipping unnecessary files during analysis.