What are TypeScript discriminated unions?

Can you explain what TypeScript discriminated unions are?

Sure! Discriminated unions in TypeScript allow you to define a type that can be one of several different types, each with a common property that acts as a discriminator.

Can you give me an example of how to use them?

Absolutely! Here's a simple example:

type Shape = 
  | { kind: 'circle'; radius: number }
  | { kind: 'square'; sideLength: number };

function area(shape: Shape) {
  switch (shape.kind) {
    case 'circle':
      return Math.PI * shape.radius ** 2;
    case 'square':
      return shape.sideLength ** 2;
  }
}

In this example, Shape can be either a circle or a square, and the kind property helps TypeScript determine which type it is.

What are the benefits of using discriminated unions?

The main benefits include type safety and better code readability. They help ensure that you handle all possible cases in your code, reducing runtime errors.

Are there any limitations to using them?

One limitation is that all types in the union must share a common property. If you have very diverse types, it might not be the best approach.