TSSLint breaks with TS 5.9.2

[kurtextrem]

TSError: ',' expected.
    at createError (/Users/jacobgross/Documents/GitHub/FramerStudio/node_modules/@typescript-eslint/typescript-estree/dist/node-utils.js:568:12)
    at convertError (/Users/jacobgross/Documents/GitHub/FramerStudio/node_modules/@typescript-eslint/typescript-estree/dist/convert.js:51:41)
    at astConverter (/Users/jacobgross/Documents/GitHub/FramerStudio/node_modules/@typescript-eslint/typescript-estree/dist/ast-converter.js:15:42)
    at parseAndGenerateServices (/Users/jacobgross/Documents/GitHub/FramerStudio/node_modules/@typescript-eslint/typescript-estree/dist/parser.js:162:66)
    at Object.parseForESLint (/Users/jacobgross/Documents/GitHub/FramerStudio/node_modules/@tsslint/eslint/node_modules/@typescript-eslint/parser/dist/parser.js:101:80)
    at getEstree (/Users/jacobgross/Documents/GitHub/FramerStudio/node_modules/@tsslint/eslint/index.js:572:69)
    at tsslintRule (/Users/jacobgross/Documents/GitHub/FramerStudio/node_modules/@tsslint/eslint/index.js:255:44)
    at Object.lint (/Users/jacobgross/.cursor/extensions/johnsoncodehk.vscode-tsslint-1.5.5-darwin-arm64/node_modules/@tsslint/core/index.js:137:21)
    at Object.info.languageService.getSemanticDiagnostics (/Users/jacobgross/.cursor/extensions/johnsoncodehk.vscode-tsslint-1.5.5-darwin-arm64/node_modules/@tsslint/typescript-plugin/index.js:146:43)

I tried upgrading @typescript-eslint/estree but that also didn't fix it. 8.36.0 to 8.38.0 are broken with TS 5.9.

[serkodev]

Same here, I'm providing more information for debug.

Seems the issue only occurs when ALL of the following conditions are met:

• convertRule from @tsslint/eslint is used
• TypeScript version is 5.9.2
• The error appears in the VSCode extension, but not in the CLI

[serkodev]

The root cause of the issue is that the tsslint VSCode plugin (the @tsslint/typescript-plugin package) uses the built-in TypeScript version bundled with VSCode, while @typescript-eslint uses the TypeScript version specified in your project.

Currently, the latest version of VSCode (v1.102.3) uses TypeScript 5.8.3 by default. Therefore, if your project uses a different TypeScript version, this mismatch can lead to errors.

TL;DR (Workaround)

You can resolve the version mismatch issue by configuring VSCode to use your workspace’s TypeScript version instead of the built-in one.

1. Click the { } icon next to "TypeScript" on your VSCode bottom bar
2. Click "Select Version" from "TypeScript version"
3. Pick "Use Workspace Version"

Or you can just past the following config in .vscode/settings.json

"typescript.tsdk": "node_modules/typescript/lib"

Alternatively, you can wait for a future VSCode update that includes a newer default TypeScript version, which may also resolve the problem.

Additional Notes

While investigating this error, I also explored the error message in more detail, hoping this information will be helpful for others.

Cause of the Error: TSError: ',' expected.

When tsslint performs linting, it retrieves the sourceFile from the ts object in context:

tsslint/packages/core/index.ts

Line 80 in df0cd4c

sourceFile: ctx.languageService.getProgram()!.getSourceFile(fileName)!,

If the TypeScript version used by VSCode is outdated, the retrieved sourceFile result will also be based on the old version.

Then, the following functions are executed in order (from top to bottom):

Object.lint (/tsslint/packages/core/index.ts:130)
tsslintRule (/tsslint/packages/eslint/index.ts:241)
getEstree (/tsslint/packages/eslint/index.ts:585)
Object.parseForESLint (/tsslint/node_modules/@typescript-eslint/parser/dist/parser.js:101)
parseAndGenerateServices (/tsslint/node_modules/@typescript-eslint/typescript-estree/dist/parser.js:100)
createParseSettings (/tsslint/node_modules/@typescript-eslint/typescript-estree/dist/parseSettings/createParseSettings.js:70)

Step into:

// enforceCodeString (/tsslint/node_modules/@typescript-eslint/typescript-estree/dist/parseSettings/createParseSettings.js:202)
function enforceCodeString(code) {
    return (0, source_files_1.isSourceFile)(code)
        ? code.getFullText(code)
        : typeof code === 'string'
            ? code
            : String(code);
}

Step into:

// isSourceFile (/tsslint/node_modules/@typescript-eslint/typescript-estree/dist/source-files.js:44)
function isSourceFile(code) {
    if (typeof code !== 'object' || code == null) {
        return false;
    }
    const maybeSourceFile = code;
    return ( maybeSourceFile.kind === ts.SyntaxKind.SourceFile &&
        typeof maybeSourceFile.getFullText === 'function');
}

In isSourceFile, it checks whether code is a TypeScript SourceFile using the ts.SyntaxKind.SourceFile enum:

• In typescript@5.9.2, this value is 308
• In typescript@5.8.3, it's 307

As a result, the check fails when the enum value doesn’t match, causing enforceCodeString to fallback to String(code), which returns [object Object].

This codeFullText = '[object Object]' is then passed to TypeScript for AST parsing, which incorrectly interprets it as the start of an array ([) and throws the error:

TSError: ',' expected.

This explains how mismatched TypeScript versions lead to such parsing issues.

[Gehbt]

Typescript@5.9 has introduced DeferKeyword(166) which is before than SouceFile(307)(now it is 308)

[serkodev]

Update: The latest VSCode v1.103.0 updated its default TypeScript version to 5.9.2, so this issue should be fixed.

On the contrary, if your project 's TypeScript is < 5.9.2 and you updated to VSCode 1.103.0, it may cause the same version mismatch issue.

[kurtextrem]

Thank you everyone, I really appreciate your insights / help on this bug. That indeed fixes it.