TypeScript language features are broken in browser-based IDE on node >= 21

[pisv]

Steps to Reproduce:

0. Use Node.JS version >= 21.

1. Build and run the browser example:

git clone https://github.com/eclipse-theia/theia \
    && cd theia \
    && npm install \
    && npm run build:browser \
    && npm run download:plugins \
    && npm run start:browser

Start your browser on http://localhost:3000.

2. Open the Theia repository root folder in the browser-based IDE. (Actually, any project in TypeScript will do, as long as it contains a valid tsconfig.json.)

3. Open a .ts source file, e.g. preference-string-input.ts.

Observe that:

• The TypeScript language features provided in the editor are limited to the current file, e.g. suggestions are only shown from the current file and Go to Definition can only jump to a symbol in the current file.

• The language status item in the status bar indicates that the current file is in partial mode, in which project-wide IntelliSense is unavailable.

• The Output view for TypeScript shows that semantic TS Server is not being used, as only syntax TS Server has been started:

[Info] Starting TS Server
[Info] Using tsserver from: /.../theia/plugins/vscode.typescript-language-features/extension/deps/typescript/lib/tsserver.js
[Info] <syntax> Forking...
[Info] <syntax> Starting...

Additional Information

Actually, I could not believe my own eyes when I saw it and spent most of the weekend trying to troubleshoot the issue, my first thought being that something should be wrong with my local setup, as I could not find any open issue for it and a problem of this kind could certainly not go unnoticed. Also, I could swear that it worked just fine a while ago. (When I was still using node 20.x, as I understand now.)

Finally, I replaced the downloaded version 1.95.3 of the vscode.typescript-language-features extension with a locally built version from the VS Code main branch, and it fixed the issue for me.

Debugging the extension then revealed that the issue is caused by this code in the older versions of typescript-language-features, which has been fixed in version 1.102.0 by this commit.

For background, see microsoft/vscode#251688 and https://code.visualstudio.com/updates/v1_101#_web-environment-detection.

• Operating System: all
• Theia Version: 1.67 and earlier

[ndoschek]

Hi @pisv, thanks for catching and raising this, that is indeed concerning.
I am currently working on updating the built-ins to version 1.104.0 and plan to open the PRs this week. I'll make this a higher priority and keep you posted on the progress.

[pisv]

Thank you @ndoschek! Updating the built-ins to version 1.104.0 should certainly fix this issue.

See also #16233, which proposes to implement a workaround for the underlying issue. Note, however, that the workaround as it is currently implemented in VS Code would not fix this issue, as older versions of typescript-language-features test for the presence of the navigator property in globalThis, while VS Code just makes this property return undefined in the extension host process (microsoft/vscode#251688 (comment)).

[ndoschek]

Hi again @pisv,
I just opened a draft PR for the built-in extensions and typescript update: #16774
If you happen to have some time and interest, I'd really appreciate your review and any testing as well.
But of course totally optional and there's no rush at all, with the holidays coming up, we’re likely looking at a merge in January anyway :)