Type checking

n8n Code-node source is a function body — top-level return/await — which plain tsc rejects in .ts files (TS1108). The typecheck behind preflight’s types check and the push gate therefore wraps node files in an async function in memory and maps diagnostics back to real line numbers. A .decanter.json next to a file — or in the parent of its code/ dir — is what marks it as a node file.

Files on disk stay verbatim: never “fix” a node file by wrapping it in a function or stripping its top-level return.

Editor false positives

The IDE’s own tsserver doesn’t apply the wrapper, so editors show a spurious TS1108/TS1375/TS1378 on top-level return/await in node files. Ignore it — n8n-decanter preflight --offline is authoritative.

Scaffolded sync dirs ship a TypeScript language-service plugin (decanter-ts-plugin/) that suppresses exactly these three codes on node files (all other diagnostics stay live). It activates once tsserver runs the workspace TypeScript: npm install, then in VS Code accept Use Workspace Version (offered via .vscode/settings.json); JetBrains uses the project TypeScript by default.

Two tsconfigs in a sync dir

The scaffolded tsconfig.json belongs to the workflow node files (with n8n-globals.d.ts typing $input, $('…'), DateTime, …). Its name is load-bearing — the typecheck discovers it by name, searching upward. Keep it where the config is.