Opinionated TypeScript guidelines for AI-assisted development -- one opinion per decision point
The TypeScript Narrows is a Claude Skill and an ESLint plugin that complement each other. Together they help AI agents narrow the "five different ways to do X" to a single, opinionated, best-practice way to do X. Some examples:
any, no !, no type assertions — narrow insteadenum — use as const objects with discriminated unions.forEach(), no .reduce() — use for...ofreturn await inside try/catch (always)?? over ||, ?. over manual null checksthrow only for bugsReadonly<T> params, readonly properties, no mutable exportsstrict: true plus noUncheckedIndexedAccessThe Claude skill and the ESLint plugin extend @typescript-eslint and cover over 50 opinions on type safety, error handling, async patters, naming conventions, and more.
"The TypeScript Narrows" is a play on "The Deathly Hallows".
docs/opinions/INDEX.md)plugin/the-typescript-narrows/skills/the-typescript-narrows/SKILL.md)eslint-plugin/)For AI-assisted development: Install the Claude plugin from the marketplace:
claude plugin add-marketplace github:sethlivingston/claude-marketplace
claude plugin install the-typescript-narrows
The skill triggers automatically when writing or reviewing TypeScript. See the plugin README for details.
For automated enforcement: Install the ESLint plugin to lint against these opinions in CI and your editor. See eslint-plugin README for setup instructions.
Both artifacts work independently, but they're designed to complement each other -- the skill covers opinions that can't be expressed as lint rules.
See docs/TRACEABILITY.md for the full traceability matrix mapping all opinions to their enforcement mechanisms.
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