Gain insights into the runtime behavior of the TypeScript code by narrowing down union types.
Continue your TypeScript learning journey with Learn TypeScript: Type Narrowing. Leverage TypeScript’s type system to gain insights into the runtime behavior of your code by narrowing down what types unions may actually be.
### Skills you’ll gain
* Understand how TypeScript utilizes type narrowing at runtime.
* Write type guards to check if a variable is a specific type.
* Check if a property exists in an object using the `in` operator.
### Notes on prerequisites
We recommend that you complete [Learn TypeScript: Union Types](https://www.codecademy.com/learn/learn-typescript-union-types) before starting this course.
Continue your TypeScript learning journey with Learn TypeScript: Type Narrowing. Leverage TypeScript’s type system to gain insights into the runtime behavior of your code by narrowing down what types unions may actually be.
### Skills you’ll gain
* Understand how TypeScript utilizes type narrowing at runtime.
* Write type guards to check if a variable is a specific type.
* Check if a property exists in an object using the `in` operator.
### Notes on prerequisites
We recommend that you complete [Learn TypeScript: Union Types](https://www.codecademy.com/learn/learn-typescript-union-types) before starting this course.
