TypeScript Strict Mode

Overview

TypeScript Strict Mode helps teams adopt and maintain the highest level of type safety. It identifies type weaknesses in your codebase and systematically replaces them with precise, strict types that catch bugs at compile time.

Key Features

• Any Elimination: Scans your codebase for `any` types and replaces them with proper types inferred from usage patterns. Handles both explicit `any` annotations and implicit `any` from missing types.
• Strict Null Checks: Identifies all potential null/undefined access patterns and adds proper null checks, optional chaining, or non-null assertions where appropriate.
• Generic Improvements: Detects functions and classes that would benefit from generics and adds type parameters that preserve type information through call chains.
• Incremental Migration: For large codebases, enables strict mode file-by-file with `// @ts-strict` comments, allowing gradual adoption without blocking the entire team.

Configuration

The skill can configure `tsconfig.json` with all strict flags: `strict`, `strictNullChecks`, `strictFunctionTypes`, `strictBindCallApply`, `noImplicitAny`, `noImplicitReturns`, and `noUncheckedIndexedAccess`.

Best Practices

Start with `noImplicitAny` and `strictNullChecks` as they catch the most bugs. Add `noUncheckedIndexedAccess` for array and object safety. Use the incremental migration mode for existing projects.