TypeScript
TypeScript Strict ModeTypeScript Strict Mode
Strict Mode forces developers to write the safest code possible.
Read Time
5 min readDifficulty
BeginnerLast Updated
Jun 15, 2026Version
v1.0.0Introduction
By default, TypeScript lets a few sloppy coding habits slide. Activating Strict Mode in the configuration file turns on the maximum level of type checking. It prevents developers from taking shortcuts, resulting in virtually bug-free code.
Key Points
- Enable it by setting `"strict": true` in `tsconfig.json`.
- It blocks the dangerous `any` type when the compiler can't guess the type.
- It prevents errors where variables might accidentally be `null` or `undefined`.
- Professional teams always keep Strict Mode turned on.