What problem does it solve?
TypeScript coding standards and conventions codify policy to promote consistency, readability, and safer, more maintainable code across projects.
Core Features & Use Cases
- no barrel files
- avoid type assertions (
as Foo or as unknown as or Foo!). do guards or Effect.schema stuff (ex is) instead
- no
void for async - use async/effect (exception vscode-window-messages)
- no
export * - name exports explicitly
- prefer
undefined over null (unless server requires null)
- prefer
undefined over empty string
- prefer map/filter over loops/conditionals
- avoid mutation
- avoid
any
- no enums or namespaces (enums compile to weird JS; use string union types instead; exception: interfaces defined outside this repo that we can't change)
- no runtime errors for developer mistakes (use types to ensure exhaustive switch/case; don't throw for null/undefined when input/consumer is within our control)
- .ts filenames: camelCase, no hyphens, no leading capitals
- preserve comments when refactoring; remove if wrong/obsolete
- exported functions: single-line jsdoc /*_ foo _/ if name unclear; no params/return (TS provides types)
- look for uses of (Object|Map).groupBy instead of older patterns
Quick Start
Follow these rules when writing or refactoring TypeScript to ensure consistent, safe code.
