Special types

Asynchronous

Data structures

The good, the bad, the ugly

The good

• Types. That's the main reason one uses TypeScript.
• Nice syntactic sugar like

The bad

• TS's type system isn't truly static - types disappear at runtime. While the compiler catches a lot of things, issue might remain when you successfully fool the compiler or don't consider what the compiler does not check. The next point applies here too.
• TS does not support real casting: Casting in TypeScript
• Programming languages/TypeScript/Enums are available but not endorsed when writing code, as they are delivered to runtime.

The ugly

• Having to write Type guards often leads to confusing syntax
• Some of TypeScripts rather advanced features like discriminated Union types and recursive type definitions can lead to abstract and difficult to understand code
• TypeScript will never solve some of the underlying issues that JavaScript intro has.
• Decorators in TypeScript differ from decorators in JavaScript

Resources

• https://kyleshevlin.com/typescript-prevents-bad-things-and-good-things/