tsdown Problem Matchers

Inspired by esbuild-problem-matchers and tsup-problem-matchers.

VS Code problem matchers for tsdown (Rolldown) CLI output, so build/watch tasks populate Problems with file, line, and column.

Builtin problem matchers

Bundled errors are matched from output like:

• \[SOME_CODE\] Error: … (message) on one line, then a second line containing path/to/file.ts:line:col inside the Rolldown pretty-printed frame (ANSI codes are tolerated). This matches tsdown 0.21.x / Rolldown 1.0.0-rc.x in this repo’s playground.

If your tsdown version changes the log format, adjust the patterns in package.json and use playground to re-check.

--dts and $tsdown-dts

Many projects still benefit from listing $tsdown-dts next to $tsdown: when TypeScript reports declaration issues in a tsc-compatible shape, they are picked up. If tsdown does not fail the build on a type mismatch (emit continues), you may rely on $tsc / editors alone — see the tsdown docs for your version’s behavior.

Usage in tasks.json

npm script, one-shot build:

{
  "version": "2.0.0",
  "tasks": [
    {
      "type": "npm",
      "script": "build",
      "group": "build",
      "problemMatcher": ["$tsdown", "$tsdown-dts"],
      "label": "npm: build"
    }
  ]
}

Watch / dev server (tsdown --watch), background task:

{
  "type": "npm",
  "script": "dev",
  "group": "build",
  "problemMatcher": ["$tsdown-watch", "$tsdown-dts-watch"],
  "isBackground": true,
  "label": "npm: dev"
}

Shell task (e.g. npm run dev --loglevel silent), like a VS Code extension repo:

{
  "label": "dev",
  "type": "shell",
  "command": "npm",
  "args": ["run", "dev", "--loglevel", "silent"],
  "isBackground": true,
  "problemMatcher": ["$tsdown-watch", "$tsdown-dts-watch"],
  "group": { "kind": "build", "isDefault": false },
  "presentation": { "reveal": "silent", "panel": "shared" }
}

Use $tsdown / $tsdown-dts for non-watch build, and $tsdown-watch / $tsdown-dts-watch when the task stays running.

Turborepo / task runners with prefixed lines

If each log line is prefixed (for example with the package name), override the background patterns while inheriting the rest, similar to tsup-problem-matchers:

{
  "problemMatcher": [
    {
      "base": "$tsdown-watch",
      "background": {
        "activeOnStart": true,
        "beginsPattern": "your-pkg-name: .*Build start",
        "endsPattern": "your-pkg-name: .*(Rebuilt in|Build complete in|at async runCLI)"
      }
    }
  ]
}

Tune beginsPattern / endsPattern to the exact prefix your runner prints.

Develop this extension

1. pnpm install at the repo root (installs @vscode/vsce for packaging).
2. Run Extension (F5): use Run and Debug and pick the appropriate launch config:
   • Opening the repo root (tsdown-problem-matchers): choose Run Extension in .vscode/launch.json. The host opens with the playground folder loaded.
   • Opening only the playground folder: if the debug sidebar asks you to create launch.json, you are not at the repo root—either File → Open Folder… and select tsdown-problem-matchers (root), or use Run Extension (develop from playground folder) in playground/.vscode/launch.json.
3. Run a task in the host window (the window that opens after F5—the one with playground as the workspace). F5 does not run tasks for you; you start them explicitly:
   • From the menu: Terminal → Run Task… (or Run Build Task if you rely on the default build task).
   • From the Command Palette (Ctrl+Shift+P / Cmd+Shift+P): run Tasks: Run Task, then pick a task by its label from playground/.vscode/tasks.json, for example:
     • playground: tsdown build (error sample) — failed build; use this to confirm $tsdown populates Problems from terminal output.
     • playground: tsdown build — successful build; playground: tsdown watch — watch mode (background task; uses $tsdown-watch).
   • From an integrated terminal in that same host window: cd to playground if needed, then run the same scripts (e.g. pnpm run build:error). Tasks are preferred when you want the configured problemMatcher applied automatically.
   • Open the Problems panel to see diagnostics (e.g. tsdown(PARSE_ERROR) from the matcher vs ts(…) from the TypeScript language service).

Package a .vsix:

pnpm run package

License

MIT License © Frankie