TypeScript Best Practices Every Frontend Developer Should Know

TypeScript has transformed how we write JavaScript. Here are the practices that have made the biggest difference in my projects. ## Use Strict Mode Always enable strict mode in your tsconfig.json. It catches more bugs at compile time: ```json { "compilerOptions": { "strict": true, "noUncheckedIndexedAccess": true, "exactOptionalPropertyTypes": true } } ``` ## Prefer Type Inference Don't annotate types when TypeScript can infer them: ```typescript // Bad — redundant annotation const count: number = 0; const name: string = 'Alice'; // Good — let TypeScript infer const count = 0; const name = 'Alice'; ``` ## Use Discriminated Unions Discriminated unions are one of TypeScript's most powerful features: ```typescript type Result<T> = | { status: 'success'; data: T } | { status: 'error'; error: string } | { status: 'loading' }; ``` ## Avoid Any and Unknown Wisely Never use `any` — it defeats the purpose of TypeScript. Use `unknown` when the type is truly unknown, then narrow it with type guards. ## Use Utility Types TypeScript's built-in utility types (`Partial`, `Required`, `Pick`, `Omit`, `Record`) reduce duplication and keep types DRY. ## Conclusion Mastering TypeScript takes time, but following these practices from day one will save you countless hours of debugging and make your code significantly more maintainable.