What is a typescript interface?
This is sometimes called “duck typing” or “structural subtyping”. In TypeScript, interfaces fill the role of naming these types, and are a powerful way of defining contracts within your code as well as contracts with code outside of your project. The easiest way to see how interfaces work is to start with a simple example:
Does TypeScript support type aliases?
TypeScript supportstype aliasesfor naming a type expression. This can be used to name primitives, unions,tuples, and any other types. However, when declaring types for objects, use interfaces instead of a typealias for the object literal expression. interface User { firstName: string; lastName: string;}
What is type checking in typescript?
One of TypeScript’s core principles is that type checking focuses on the shape that values have. This is sometimes called “duck typing” or “structural subtyping”. In TypeScript, interfaces fill the role of naming these types, and are a powerful way of defining contracts within your code as well as contracts with code outside of your project.
How does TypeScript compiler check for excess properties on an object?
The TypeScript compiler also checks for excess properties on an object and gives an error if an object contains a property that is defined in the interface We also learned how to define Indexable properties using interfaces Classes can implement an interface. The interface contains the definition for only the instance variables of a class
typescript-handbook.pdf