Creating interfaces

Understanding an interface

An interface allows a new type to be created with a name and structure. The structure includes all the properties and methods that the type has without any implementation.

Interfaces don’t exist in JavaScript; they are only used by the TypeScript compiler type checking process.

Creating an interface

We create an interface with the interface keyword, followed by its name, followed by the properties and methods that make up the interface in curly brackets:

interface TypeName {
  propertyName: PropertyType;
  methodName: (paramName: ParamType) => MethodReturnType
}

As an exercise, create an interface called ButtonProps that has a text property of type string and an onClick method that has no parameters and doesn’t return anything. We should be able ...