Unlocking the Power of Union Types in TypeScript

Discover how Union Types in TypeScript can enhance your code flexibility and type safety, allowing you to handle diverse data structures with ease.

The Basics of Union Types

Union types in TypeScript allow you to combine multiple types into one. This feature provides flexibility when a variable can have different types of values.

Defining Union Types

Let's consider a simple example:

type Result = Success | Failure; type Success = { success: true, data: string }; type Failure = { success: false, error: string };

In this example, the 'Result' type can either be a 'Success' or a 'Failure' type.

Using Union Types

Union types are useful in scenarios where a function can return different types of values:

function processData(data: string | number): string | number { return data; }

This function can accept either a string or a number and return the same type.

Type Guards with Union Types

Type guards help narrow down the possible types within a union:

function printData(data: string | number) { if (typeof data === 'string') { console.log(data.toUpperCase()); } else { console.log(data.toFixed(2)); }}

By using type guards, you can safely access properties or methods specific to a certain type.

Intersection Types vs. Union Types

While union types allow for flexibility, intersection types combine multiple types:

type Admin = User & Role; type User = { name: string }; type Role = { role: string };

With intersection types, you can merge properties from different types.

Enhancing Type Safety

Union types improve type safety by explicitly defining all possible types a variable can have. This reduces the chances of runtime errors.

Conclusion

Union types in TypeScript offer a powerful way to handle diverse data structures and improve code flexibility. By leveraging union types effectively, you can write more robust and maintainable code.