Skillshub TypeScript Language Patterns

Modern TypeScript standards for type safety and maintainability. Use when working with types, interfaces, generics, enums, unions, or tsconfig settings.

install

source · Clone the upstream repo

git clone https://github.com/ComeOnOliver/skillshub

Claude Code · Install into ~/.claude/skills/

T=$(mktemp -d) && git clone --depth=1 https://github.com/ComeOnOliver/skillshub "$T" && mkdir -p ~/.claude/skills && cp -r "$T/skills/HoangNguyen0403/agent-skills-standard/language" ~/.claude/skills/comeonoliver-skillshub-typescript-language-patterns && rm -rf "$T"

manifest: skills/HoangNguyen0403/agent-skills-standard/language/SKILL.md

source content

TypeScript Language Patterns

Priority: P0 (CRITICAL)

Implementation Guidelines

Type Annotations: Explicit params/returns. Infer locals.
Interfaces vs Types:
```
interface
```
for APIs.
```
type
```
for unions.
Strict Mode:
```
strict: true
```
. Null Safety:
```
?.
```
and
```
??
```
.
Enums: Literal unions or
```
as const
```
. No runtime
enum
.
Generics: Reusable, type-safe code.
Type Guards:
```
typeof
```
,
```
instanceof
```
, predicates.
Utility Types:
```
Partial
```
,
```
Pick
```
,
```
Omit
```
,
```
Record
```
.
Immutability:
```
readonly
```
arrays/objects. Const Assertions:
```
as const
```
,
```
satisfies
```
.
Template Literals:
```
on${Capitalize<string>}
```
.
Discriminated Unions: Literal
```
kind
```
property.
Advanced: Mapped, Conditional, Indexed types.
Access: Default
```
public
```
. Use
```
private
```
/
```
protected
```
or
```
#private
```
.
Branded Types:
```
string & { __brand: 'Id' }
```
.

Anti-Patterns

No
any
: NEVER use
```
any
```
. Use
```
unknown
```
or specific interfaces.
No
Function
: Use signature
```
() => void
```
.
No
enum
: Runtime cost.
No
!
: Use narrowing.
NO LINT DISABLE: PROHIBITED. Fix issues properly.

Testing

Mocking: Use
```
jest.Mocked<T>
```
or
```
as unknown as T
```
.
Checklist: Check method existence, match error constants, satisfy required properties.
References: See references/TESTING.md for common issues/solutions.

Code

// Branded Type
type UserId = string & { __brand: 'Id' };

// Satisfies (Validate + Infer)
const cfg = { port: 3000 } satisfies Record<string, number>;

// Discriminated Union
type Result<T> = { kind: 'ok'; data: T } | { kind: 'err'; error: Error };

Reference & Examples

For advanced type patterns and utility types: See references/REFERENCE.md.