TypeScript Special Types

TypeScript Special Types

They help you write safer, clearer, and more predictable code.

any

Disables type checking ( not recommended).

•  Avoid any in large projects—it removes TypeScript’s benefits.

unknown (Safer than any)

You must check the type before using it.

•  Preferred over any.

void

Used when a function returns nothing.

never

Used when a function never completes (throws error or infinite loop).

null and undefined

Represent absence of value.

With strict mode:

object

Represents non-primitive values.

•  Use specific object types for better safety.

Type Assertions (as)

Tell TypeScript you know the type.

Or:

•  Assertion ≠ type conversion.

bigint

Used for very large integers.

 Literal Types

Restrict variables to exact values.

symbol

Creates unique identifiers.

Special Types Summary

Best Practices

• Avoid any
•  Prefer unknown
•  Use never for unreachable code
• Use literal types for strict values