Advanced type inference

The TypeScript language has given us a large toolbox with which to define custom types, inherit types from each other, and use generic syntax to work with any number of different types. By combining these features, we can start to describe some seriously advanced type definitions, including types based on other types, or types based on some or all of the properties of another type. We can also completely modify a type by adding and removing properties as we see fit.

In this section of the chapter, we will explore more advance type inference, including conditional types, inferred types, and mapped types, or, as the author describes it, "type mathematics." Be warned that the syntax used with advance types can quickly become rather complicated to read, but if we apply some simple rules, it is easily understandable.

Remember that although types help us to describe our code, and also help to harden our code, they do not affect the generated JavaScript...