You must know the difference between Unknown and Any in Typescript

Hey everyone,

I wrote an insightful article comparing TypeScript's unknown and any types. These types come in handy when we're dealing with variables of uncertain or dynamic types.

Unknown Type
Introduced in TypeScript 3.0, unknown is a safer alternative to any. It represents a value that can have any type, but with stricter type checking. This means you can't directly assign or access properties/methods on unknown variables without proper type assertions or checks.

Any Type
On the other hand, any is the most flexible type in TypeScript. It essentially bypasses type checking, allowing variables of this type to be assigned to any value or type without causing compilation errors.

Use Cases and Advantages:

Unknown:

• Improved type safety
• Refinement through narrowing
• Interoperability with JavaScript

Any:

• Rapid prototyping
• Migration from JavaScript to TypeScript
• Working with complex third-party libraries

Pitfalls and Best Practices:

Pitfalls of Unknown:

• Code can become verbose due to additional type checks and assertions.
• Deeply nested type checks can lead to complexity.
• Failing to perform proper type checks can still result in runtime errors.

Pitfalls of Any:

• Lack of type safety, which can lead to subtle bugs.
• Loss of type information, affecting development efficiency.
• Reduced maintainability as codebase grows.

Best Practices:

• Prefer unknown over any for flexibility with type safety.
• Utilize type guards and assertions with unknown.
• Gradually replace any with more specific types during migration.
• Provide clear documentation when using any.
• Enforce code reviews to catch improper usage.

In conclusion, both unknown and any have their specific purposes. Don't forget to visit the article for in-depth explanations.

What are your thoughts on this? Do you find yourself using one type more than the other in your projects? Let's discuss!

Comments

[Felicia Walker]

Thank you, this is basic but reinforces what I had gathered about this topic. I understand why unknown is better, but doing proper checks, especially with generics or complex types, really is a headache.

[Rajae Robinson]

You're welcome! I completely understand your sentiment.