typescript-patterns
Skill2 starsChanged 7 days agoMITView on GitHub
TypeScript patterns for strictness flags, type-safety anti-patterns, and a review checklist covering any vs unknown, satisfies, branded types, discriminated unions, generic constraints, and module boundaries. Use whenever the project contains `.ts`/`.tsx` files, a `tsconfig*.json`, or `typescript` in `package.json`, OR the user asks about TypeScript, its type system, or its compiler config, even if "TypeScript" is not mentioned by name.
8 other projects use a version of this.
Adopted by
Most recently taken up by
- MMACABRE/SKILLStheir own version, first seen Nov 8, 2026
- reddygopalkrishna/developer-agent-skillstheir own version, first seen Nov 8, 2026
- mikulgohil/claude-skillstheir own version, first seen Oct 13, 2026
- sabahattink/antigravity-fullstack-hqtheir own version, first seen Sep 20, 2026
- techmefr/mentistheir own version, first seen Sep 11, 2026
- bjornjee/skillstheir own version, first seen Sep 8, 2026
Other versions8 projects use a version of this.
Word for word · 0
None found.
Edited · 0
None found.
Wrote their own version · 8
- cohen-liel/hivemind★ 108same name
- sabahattink/antigravity-fullstack-hq★ 30same name
- reddygopalkrishna/developer-agent-skills★ 8same name
- peopleforrester/claude-dotfiles★ 3same name
- bjornjee/skills★ 2same name
- MMACABRE/SKILLS★ 1same name
- mikulgohil/claude-skills★ 0same name
- techmefr/mentis★ 0same name
How matches are found. Word for word: the exact same text. Edited: shares passages with this file (“99% same” means 99% of its five-word phrases also appear here; 10% or more counts). Their own version: similar meaning, or, weakest, the same name. We can’t tell which project had it first. Projects are counted among the 200 most-starred candidates, and mentions are links to the repository we found, up to 50 per site, so both counts are a floor.
In this repository37 other files it gives its agents.
- CLAUDE.mdCLAUDE.md
- templates/CLAUDE.mdCLAUDE.md
- auditSkill
- backup-patternsSkill
- bash-patternsSkill
- depsSkill
- django-patternsSkill
- docker-patternsSkill
- drf-patternsSkill
- engineering-fundamentalsSkill
- fastapi-patternsSkill
- git-patternsSkill
- go-patternsSkill
- graphql-patternsSkill
- investigateSkill
- javascript-patternsSkill
- logging-patternsSkill
- referenceSkill
- metaSkill
- monitoring-patternsSkill
- next-app-router-patternsSkill
- nuxt-patternsSkill
- opentofu-patternsSkill
- prSkill
- python-patternsSkill
- react-patternsSkill
- report-formatSkill
- security-patternsSkill
- slop-patternsSkill
- storybook-patternsSkill
- tailwind-patternsSkill
- test-patternsSkill
- unslopSkill
- vps-provisioningSkill
- vue-patternsSkill
- wcag-auditSkill
- writeSkill
The file
We split this skill into the rules it gives an agent
3 rules. 0 are common, 0 are distinctive, and 3 are very specific to this project.
0
Common
Most of the 4 edited versions we read keep these.
0
Distinctive
This author's own choices. Worth a look.
3
Very specific
Tied to their project's names, files or tools. Probably skip.
- Common
- Distinctive
- Very specific
- Very specific: line 8
Default assumption: a TypeScript project with strict mode enabled.
- Very specific: line 10
If strict is off, that itself is a finding.
- Very specific: line 11
Verify version-sensitive claims (which flags exist, which syntax is available) against the typescript version pinned in the project's …
“Common” is measured: kept by at least 6 in 10 of the 4 edited versions of this file we could read. “Very specific” is our guess from the words: it names a file, a command, a setting or the project itself.
Files
TypeScript patterns
Default assumption: a TypeScript project with strict mode enabled.
- If
strictis off, that itself is a finding. - Verify version-sensitive claims (which flags exist, which syntax is available) against the
typescriptversion pinned in the project'spackage.jsonand lockfile before applying deltas below.
Reference files
| File | Covers |
| reference/strictness.md | Strictness flags, tsconfig review, incremental migration patterns |
| reference/type-expressions.md | unknown vs any, satisfies, discriminated unions, branded types, generic constraints, common patterns |
| reference/narrowing.md | typeof / in / instanceof, predicates, exhaustiveness, assertNever |
| reference/module-boundaries.md | import type, project references, circular imports, barrel-file anti-pattern |
| reference/anti-patterns.md | Twelve review-time anti-patterns with severity calls |
References
- TypeScript handbook: https://www.typescriptlang.org/docs/handbook/
- tsconfig reference: https://www.typescriptlang.org/tsconfig
- Release notes index: https://www.typescriptlang.org/docs/handbook/release-notes/overview.html
satisfiesoperator (4.9): https://devblogs.microsoft.com/typescript/announcing-typescript-4-9/- Variance annotations (4.7): https://devblogs.microsoft.com/typescript/announcing-typescript-4-7/
verbatimModuleSyntaxandconsttype parameters (5.0): https://devblogs.microsoft.com/typescript/announcing-typescript-5-0/- typescript-eslint rules (
no-empty-object-type,prefer-ts-expect-error,no-explicit-any): https://typescript-eslint.io/rules/ - Vercel: package import optimization (barrel files): https://vercel.com/blog/how-we-optimized-package-imports-in-next-js
Version notes
Checked: 2026-09-26 against https://devblogs.microsoft.com/typescript/ and Context7 /microsoft/typescript
- 7.0 (2026-07, latest 7.0.2): native Go compiler. Removed the options 6.0 deprecated:
modulenone/amd/umd/system,moduleResolutionnode10/classic,baseUrl,outFile,downlevelIteration,target: ES5,alwaysStrict: false,esModuleInterop: false,allowSyntheticDefaultImports: false. A tsconfig using any of these does not compile on 7. - 6.0: last JavaScript-based compiler; deprecated the options above.
- 5.0 (2023-03):
verbatimModuleSyntax,consttype parameters. 4.9:satisfies. 4.7:in/outvariance annotations.
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Your trail
Files you open will collect here, so you can find them again.
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