ts-config · diff
git:20260904.5f1d30f to git:20260927.43a351c
16 added, 14 removed. Audit A to A.
---
name: ts-config
- description: "Use when creating or migrating a tsconfig.json, choosing module/moduleResolution, or fixing TS 6.0 deprecation errors. Not for language syntax (ts-language-patterns)."
+ description: "Use when creating or migrating a tsconfig.json, choosing module/moduleResolution, or fixing TS 6.0 deprecations that are hard errors in TS 7.0. Not for language syntax (ts-language-patterns)."
versions:
- typescript: "6.0"
+ typescript: "7.0"
node: "24"
- bun: "1.3"
+ bun: "1.4"
user-invocable: false
references: references/bundler-track.md, references/node-track.md, references/deprecations-6.md, references/templates/tsconfig.bundler.md, references/templates/tsconfig.node.md
related-skills: ts-language-patterns, solid-generic
---
<objective>
- This skill covers the two supported TypeScript 6.0 config tracks for 2026 — bundler (Bun,
+ This skill covers the two supported TypeScript 7.0 config tracks for 2026 — bundler (Bun,
Vite, esbuild, webpack: module Preserve + moduleResolution bundler) and Node (pure Node.js
native type stripping: module nodenext + moduleResolution nodenext) — and how to pick
between them by runtime.
- It also covers the TS 6.0 deprecation cleanup ahead of 7.0: dropping moduleResolution
- node/node10, setting verbatimModuleSyntax, strict + noUncheckedIndexedAccess, explicit
- types, and explicit rootDir now that 6.0 no longer infers it.
+ It also covers the TS 6.0 deprecation cleanup that TS 7.0 (native Go compiler) enforces as
+ hard errors: dropping moduleResolution node/node10, setting verbatimModuleSyntax, strict +
+ noUncheckedIndexedAccess, explicit types, and explicit rootDir now that it is no longer
+ inferred.
Out of scope: TypeScript language syntax and idioms belong to ts-language-patterns;
framework configs that ship their own tsconfig base (Next.js/Astro/Vite plugin skills) and
non-TS build tooling are not covered.
</objective>
- # TypeScript Config (TS 6.0)
+ # TypeScript Config (TS 7.0)
## Agent Workflow (MANDATORY)
Before writing any tsconfig, spawn 3 agents in parallel, one `Agent` call each with a `name`:
1. **fuse-ai-pilot:explore-codebase** - Detect runtime (Bun/Node/bundler), existing tsconfig, `package.json` `type`
2. **fuse-ai-pilot:research-expert** - Confirm current flags on typescriptlang.org release notes + runtime docs
3. **mcp__context7__query-docs** - `/microsoft/typescript` for any flag whose behavior is unclear
After writing, run **fuse-ai-pilot:sniper** for validation.
---
## Overview
There are exactly **two supported config trajectories** in 2026. Pick by runtime, never mix.
| Track | Runtime | `module` | `moduleResolution` |
|-------|---------|----------|--------------------|
| **Bundler** | Bun, Vite, esbuild, webpack | `Preserve` | `bundler` |
| **Node** | Pure Node.js (native type stripping) | `nodenext` | `nodenext` |
---
## Critical Rules
- 1. **Never `moduleResolution: node` / `node10`** - deprecated in 6.0, removed in 7.0. Use `bundler` or `nodenext`.
+ 1. **Never `moduleResolution: node` / `node10`** - deprecated in 6.0, hard error in 7.0. Use `bundler` or `nodenext`.
2. **Always `verbatimModuleSyntax: true`** - both tracks. Forces explicit `import type`, matches Node's type stripping.
- 3. **`strict` + `noUncheckedIndexedAccess`** - strict is the 6.0 default; add `noUncheckedIndexedAccess` explicitly.
- 4. **Set `types` explicitly** - 6.0 defaults `types` to `[]`. Add `["node"]`, `["bun"]`, etc. or you lose globals.
- 5. **Set `rootDir` when sources are nested** - 6.0 defaults `rootDir` to the tsconfig dir, no longer inferred.
+ 3. **`strict` + `noUncheckedIndexedAccess`** - strict is the default since 6.0 (kept in 7.0); add `noUncheckedIndexedAccess` explicitly.
+ 4. **Set `types` explicitly** - since 6.0 (kept in 7.0) `types` defaults to `[]`. Add `["node"]`, `["bun"]`, etc. or you lose globals.
+ 5. **Set `rootDir` when sources are nested** - since 6.0 (kept in 7.0) `rootDir` defaults to the tsconfig dir, no longer inferred.
---
## Decision: which track?
```
Runs on Bun, or bundled by Vite/esbuild/webpack/Parcel?
→ Bundler track → references/bundler-track.md
Runs directly on `node file.ts` (type stripping), or emits .js for Node?
→ Node track → references/node-track.md
Migrating an existing 5.x config / seeing deprecation errors?
→ references/deprecations-6.md (do this first, then pick a track)
```
---
## Reference Guide
### Concepts
| Topic | Reference | When to Consult |
|-------|-----------|-----------------|
| **Bundler track** | [bundler-track.md](references/bundler-track.md) | Load when configuring a Bun or bundler (Vite/esbuild/webpack) project |
| **Node track** | [node-track.md](references/node-track.md) | Load when configuring a pure Node.js project with native type stripping |
- | **6.0 deprecations** | [deprecations-6.md](references/deprecations-6.md) | Load when migrating from TS 5.x or fixing deprecation errors |
+ | **6.0 deprecations / 7.0 errors** | [deprecations-6.md](references/deprecations-6.md) | Load when migrating from TS 5.x/6.0, fixing deprecation errors, or adopting the TS 7.0 `tsc` |
### Templates
| Template | When to Use |
|----------|-------------|
| [tsconfig.bundler.md](references/templates/tsconfig.bundler.md) | Complete Bun/bundler tsconfig |
| [tsconfig.node.md](references/templates/tsconfig.node.md) | Complete pure-Node tsconfig |
---
## Quick Reference
### Bundler / Bun
```jsonc
{
"compilerOptions": {
"module": "Preserve",
"moduleResolution": "bundler",
"verbatimModuleSyntax": true,
"allowImportingTsExtensions": true,
"noEmit": true,
"strict": true,
"noUncheckedIndexedAccess": true
}
}
```
### Pure Node.js (native type stripping)
```jsonc
{
"compilerOptions": {
"module": "nodenext",
"rewriteRelativeImportExtensions": true,
"erasableSyntaxOnly": true,
"verbatimModuleSyntax": true,
"noEmit": true, // only if you never emit .js
"strict": true
}
}
```
---
## Best Practices
### DO
- - Add `"ignoreDeprecations": "6.0"` **temporarily** while migrating, then remove it before adopting TS 7.0
+ - Add `"ignoreDeprecations": "6.0"` **temporarily** on TS 6.0 while migrating, then remove it — TS 7.0 does not honour it (deprecated options are hard errors)
+ - Keep tools that need the compiler API (e.g. typescript-eslint) on TS 6 via the `@typescript/typescript6` alias while `tsc` runs TS 7.0 — see [deprecations-6.md](references/deprecations-6.md)
- Use subpath imports `"#/*": "./src/*"` in `package.json` `imports` (supported under `nodenext` and `bundler`)
- Fold any `baseUrl` prefix into each `paths` entry (`baseUrl` is deprecated)
### DON'T
- Mix `module: Preserve` with `moduleResolution: nodenext` (or vice-versa)
- Set `esModuleInterop`, `allowSyntheticDefaultImports`, or `alwaysStrict` to `false` (no longer allowed)
- Use `enum`, `namespace` with runtime code, or parameter properties in files run by Node's type stripping