strict-typescript-mode

Name: strict-typescript-mode
Author: Svenja-dev

24installs5forks

How to install strict-typescript-mode?

svenja-dev/claude-code-skills/strict-typescript-mode

$npx -y skills add Svenja-dev/claude-code-skills --skill strict-typescript-mode

Installs into the current project.

Summary

Enforces TypeScript best practices when writing code. Automatically enables strict typing for TypeScript projects, prevents any usage, and recommends generic constraints. Activate on TS/TSX files, new features, code reviews.

Files · 1

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SKILL.md

1	# Strict TypeScript Mode
2
3	This skill enforces TypeScript best practices based on the State-of-the-Art Guide 2025.
4
5	## When to Activate
6
7	- When working with `.ts` or `.tsx` files
8	- On new feature implementations
9	- During code reviews
10	- When refactoring JavaScript to TypeScript
11
12	## Strict Rules
13
14	### 1. NEVER use `any` without documentation
15
16	```typescript
17	// FORBIDDEN
18	function process(data: any) { ... }
19
20	// ALLOWED (with justification)
21	// eslint-disable-next-line @typescript-eslint/no-explicit-any
22	// Reason: External API returns untyped data, validated at runtime
23	function processExternal(data: any) { ... }
24
25	// BETTER: Use unknown with Type Guard
26	function process(data: unknown): ProcessedData {
27	if (!isValidData(data)) throw new Error('Invalid data');
28	return data as ProcessedData;
29	}
30	```
31
32	### 2. Explicit Types for Public APIs
33
34	```typescript
35	// FORBIDDEN: Implicit return types on exports
36	export const calculate = (x, y) => x + y;
37
38	// REQUIRED: Explicit types
39	export const calculate = (x: number, y: number): number => x + y;
40
41	// For React Components
42	interface ButtonProps {
43	label: string;
44	onClick: () => void;
45	variant?: 'primary' \| 'secondary';
46	}
47
48	export const Button = ({ label, onClick, variant = 'primary' }: ButtonProps) => { ... };
49	```
50
51	### 3. Use Generic Constraints
52
53	```typescript
54	// FORBIDDEN: Unbounded generic
55	function getValue<T>(obj: T, key: string) {
56	return obj[key]; // Error
57	}
58
59	// REQUIRED: Constrained generic
60	function getValue<T extends object, K extends keyof T>(obj: T, key: K): T[K] {
61	return obj[key];
62	}
63	```
64
65	### 4. Leverage Utility Types
66
67	```typescript
68	// Instead of duplication:
69	interface UserBase { name: string; email: string; }
70	interface UserCreate { name: string; email: string; }
71	interface UserUpdate { name?: string; email?: string; }
72
73	// Use Utility Types:
74	interface User { id: string; name: string; email: string; createdAt: Date; }
75	type UserCreate = Omit<User, 'id' \| 'createdAt'>;
76	type UserUpdate = Partial<Pick<User, 'name' \| 'email'>>;
77	```
78
79	### 5. Readonly for Immutability
80
81	```typescript
82	interface Config {
83	readonly apiUrl: string;
84	readonly timeout: number;
85	}
86
87	// For arrays
88	const items: readonly string[] = ['a', 'b'];
89	// or
90	const items: ReadonlyArray<string> = ['a', 'b'];
91	```
92
93	### 6. Const Assertions for Literals
94
95	```typescript
96	// Without const assertion
97	const STATUS = { ACTIVE: 'active', INACTIVE: 'inactive' };
98	// Type: { ACTIVE: string; INACTIVE: string }
99
100	// With const assertion
101	const STATUS = { ACTIVE: 'active', INACTIVE: 'inactive' } as const;
102	// Type: { readonly ACTIVE: "active"; readonly INACTIVE: "inactive" }
103	```
104
105	### 7. Discriminated Unions for State
106
107	```typescript
108	// Instead of optional properties:
109	interface Response {
110	data?: Data;
111	error?: Error;
112	loading?: boolean;
113	}
114
115	// Use Discriminated Unions:
116	type Response =
117	\| { status: 'loading' }
118	\| { status: 'success'; data: Data }
119	\| { status: 'error'; error: Error };
120	```
121
122	## Recommended tsconfig.json
123
124	```json
125	{
126	"compilerOptions": {
127	"strict": true,
128	"noImplicitAny": true,
129	"strictNullChecks": true,
130	"strictFunctionTypes": true,
131	"noUncheckedIndexedAccess": true,
132	"noImplicitOverride": true,
133	"noUnusedLocals": true,
134	"noUnusedParameters": true,
135	"noFallthroughCasesInSwitch": true,
136	"forceConsistentCasingInFileNames": true
137	}
138	}
139	```
140
141	## Pre-Edit Checklist
142
143	- [ ] No `any` without documented reason
144	- [ ] Explicit types on exports
145	- [ ] Generic constraints where applicable
146	- [ ] Utility types instead of duplication
147	- [ ] Readonly where immutability is desired
148	- [ ] Discriminated unions for states
149
150	## On Violation
151
152	1. Issue a warning with a specific improvement suggestion
153	2. Show a code example for the correct approach
154	3. Link to TypeScript Handbook for complex cases
155
156	## Exceptions (require documentation)
157
158	- Legacy code migration (temporary)
159	- Third-party library interop
160	- Performance-critical hot paths (with benchmark evidence)

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Type

strict-typescript-mode

24installs5forks

View on GitHub

How to install strict-typescript-mode?

svenja-dev/claude-code-skills/strict-typescript-mode

$npx -y skills add Svenja-dev/claude-code-skills --skill strict-typescript-mode

Installs into the current project.

Summary

Files · 1

View on GitHub

SKILL.md

1	# Strict TypeScript Mode
2
3	This skill enforces TypeScript best practices based on the State-of-the-Art Guide 2025.
4
5	## When to Activate
6
7	- When working with `.ts` or `.tsx` files
8	- On new feature implementations
9	- During code reviews
10	- When refactoring JavaScript to TypeScript
11
12	## Strict Rules
13
14	### 1. NEVER use `any` without documentation
15
16	```typescript
17	// FORBIDDEN
18	function process(data: any) { ... }
19
20	// ALLOWED (with justification)
21	// eslint-disable-next-line @typescript-eslint/no-explicit-any
22	// Reason: External API returns untyped data, validated at runtime
23	function processExternal(data: any) { ... }
24
25	// BETTER: Use unknown with Type Guard
26	function process(data: unknown): ProcessedData {
27	if (!isValidData(data)) throw new Error('Invalid data');
28	return data as ProcessedData;
29	}
30	```
31
32	### 2. Explicit Types for Public APIs
33
34	```typescript
35	// FORBIDDEN: Implicit return types on exports
36	export const calculate = (x, y) => x + y;
37
38	// REQUIRED: Explicit types
39	export const calculate = (x: number, y: number): number => x + y;
40
41	// For React Components
42	interface ButtonProps {
43	label: string;
44	onClick: () => void;
45	variant?: 'primary' \| 'secondary';
46	}
47
48	export const Button = ({ label, onClick, variant = 'primary' }: ButtonProps) => { ... };
49	```
50
51	### 3. Use Generic Constraints
52
53	```typescript
54	// FORBIDDEN: Unbounded generic
55	function getValue<T>(obj: T, key: string) {
56	return obj[key]; // Error
57	}
58
59	// REQUIRED: Constrained generic
60	function getValue<T extends object, K extends keyof T>(obj: T, key: K): T[K] {
61	return obj[key];
62	}
63	```
64
65	### 4. Leverage Utility Types
66
67	```typescript
68	// Instead of duplication:
69	interface UserBase { name: string; email: string; }
70	interface UserCreate { name: string; email: string; }
71	interface UserUpdate { name?: string; email?: string; }
72
73	// Use Utility Types:
74	interface User { id: string; name: string; email: string; createdAt: Date; }
75	type UserCreate = Omit<User, 'id' \| 'createdAt'>;
76	type UserUpdate = Partial<Pick<User, 'name' \| 'email'>>;
77	```
78
79	### 5. Readonly for Immutability
80
81	```typescript
82	interface Config {
83	readonly apiUrl: string;
84	readonly timeout: number;
85	}
86
87	// For arrays
88	const items: readonly string[] = ['a', 'b'];
89	// or
90	const items: ReadonlyArray<string> = ['a', 'b'];
91	```
92
93	### 6. Const Assertions for Literals
94
95	```typescript
96	// Without const assertion
97	const STATUS = { ACTIVE: 'active', INACTIVE: 'inactive' };
98	// Type: { ACTIVE: string; INACTIVE: string }
99
100	// With const assertion
101	const STATUS = { ACTIVE: 'active', INACTIVE: 'inactive' } as const;
102	// Type: { readonly ACTIVE: "active"; readonly INACTIVE: "inactive" }
103	```
104
105	### 7. Discriminated Unions for State
106
107	```typescript
108	// Instead of optional properties:
109	interface Response {
110	data?: Data;
111	error?: Error;
112	loading?: boolean;
113	}
114
115	// Use Discriminated Unions:
116	type Response =
117	\| { status: 'loading' }
118	\| { status: 'success'; data: Data }
119	\| { status: 'error'; error: Error };
120	```
121
122	## Recommended tsconfig.json
123
124	```json
125	{
126	"compilerOptions": {
127	"strict": true,
128	"noImplicitAny": true,
129	"strictNullChecks": true,
130	"strictFunctionTypes": true,
131	"noUncheckedIndexedAccess": true,
132	"noImplicitOverride": true,
133	"noUnusedLocals": true,
134	"noUnusedParameters": true,
135	"noFallthroughCasesInSwitch": true,
136	"forceConsistentCasingInFileNames": true
137	}
138	}
139	```
140
141	## Pre-Edit Checklist
142
143	- [ ] No `any` without documented reason
144	- [ ] Explicit types on exports
145	- [ ] Generic constraints where applicable
146	- [ ] Utility types instead of duplication
147	- [ ] Readonly where immutability is desired
148	- [ ] Discriminated unions for states
149
150	## On Violation
151
152	1. Issue a warning with a specific improvement suggestion
153	2. Show a code example for the correct approach
154	3. Link to TypeScript Handbook for complex cases
155
156	## Exceptions (require documentation)
157
158	- Legacy code migration (temporary)
159	- Third-party library interop
160	- Performance-critical hot paths (with benchmark evidence)

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Type