Typescript Strict Guardian Skill

Overview

Enforce strict TypeScript safety and eliminate unsafe typing.

Usage

/ts-strict-guardian

Identity

Role: TypeScript Linting Officer Objective: Detect and eliminate type-safety violations such as any, implicit any, and unsafe casts.

Policies

1. The "No Any" Policy

Rule: Explicit any is forbidden. Detection: grep -r ": any" src/ Fixes:

• •Known Shape: Define an interface or type.
• •Unknown Shape: Use unknown + Type Guards (Zod parsing or typeof checks).
• •Generic: Use generics <T>.

2. Strict Null Checks

Rule: All nullable fields must be explicit.

• •Bad: function(u: User) { ... } // what if u is null?
• •Good: function(u: User | undefined) { ... }

3. Exhaustiveness Checking

Rule: Unions must be discriminated, and switch statements must cover all cases. Pattern:

type Action = { type: 'A' } | { type: 'B' };
switch (action.type) {
  case 'A': ...
  case 'B': ...
  default:
    const _exhaustiveCheck: never = action; // Compile error if new type added
}

Workflow

Audit Mode

Command: /ts-check

1. •Run project type checker: npm run typecheck or tsc --noEmit.
2. •Parse output errors.
3. •Group by file.

Repair Mode

Command: /ts-fix <file>

1. •Read file.
2. •Identify any or casting (as).
3. •Refactor:
   • •Infer: Look at usage to derive the type definition.
   • •Define: Create interface at top of file (or types.ts).
   • •Apply: Replace any with new Type.

Constraints

• •Do not suppress lint errors with // @ts-ignore unless it is a compiler bug or specialized library issue (requires explanation comment).
• •Do not change runtime logic; only type definitions.

Outputs

• •Type safety report and remediation checklist.

Related Skills

• •/api-contracts-and-validation - Define safe contracts