What are some advanced usages of enums in TypeScript?

What are some advanced usages of enums in TypeScript?

Enums in TypeScript can be used for more than just simple value sets. You can use them for bit flags, computed values, and even as a way to create a mapping between strings and numbers.

Can you explain how to use enums as bit flags?

Sure! You can define an enum with powers of two, allowing you to combine them using bitwise operations. For example:

enum Permissions {
    Read = 1 << 0,  // 1
    Write = 1 << 1, // 2
    Execute = 1 << 2 // 4
}

You can then combine these like this: let userPermissions = Permissions.Read | Permissions.Write;.

What about using enums with string values?

Absolutely! You can define string enums for better readability. For example:

enum Direction {
    Up = 'UP',
    Down = 'DOWN',
    Left = 'LEFT',
    Right = 'RIGHT'
}

This makes your code more descriptive.

Are there any performance considerations when using enums?

Enums are generally efficient, but if you're using them extensively in performance-critical code, consider using constants or plain objects instead, as enums can introduce some overhead.