Should interface be in separate file?
When you don’t declare a package, a type is in the default package. So even if you just put the IServiceAnnouncer interface in a separate file, it will be available to HelloWorld . Just compile both files at the same time. Thus, it’s preferred to place public (and also non-public, btw) classes in separate files.
Should interface always have a single method?
It must always use a class that implements all methods of the interface. So as a common guideline, one can say: If a class that only exposes a single method to the client code might be useful to some client, then using a single method interface for that method is a good idea.
What is a namespace in TS?
The namespace is used for logical grouping of functionalities. A namespace can include interfaces, classes, functions and variables to support a single or a group of related functionalities. A namespace can be created using the namespace keyword followed by the namespace name.
Should I use typescript namespaces?
Typescript is a superset of ES6 so you have more power in what you can do, but that doesn’t mean you should do it. In this case, ES6 solved the problem of modularization for us by doing a good job, so we don’t need any namespace at all in common programs (unless you specifically want to use namespaces).
Are TypeScript namespaces deprecated?
Namespaces are not being removed from TypeScript!
When do I need to use interfaces when only one class?
Interfaces are a tool for defining contractsbetween multiple subsystems of your application; so what really matters is how your application is divided into subsystems. There should be interfaces as the front-end to encapsulated subsystems, no matter how many classes implement them.
Do you need to know the interface definition?
In a different project, you may have to know the interface definition, but it is not at all necessary to know any concrete class implementing it – especially when you use an IoC container. So those other projects only need to reference the interface projects, not the implementation projects.
Is the interface in the same assembly as the implementation?
The only downside I see of having the interface in the same assembly as the implementation is that the whole assembly (including the unused implementation) will have been loaded.
What do you need to know about the Interface Segregation Principle?
The Interface Segregation Principle (ISP) states that a client should not be exposed to methods it doesn’t need. Declaring methods in an interface that the client doesn’t need pollutes the interface and leads to a “bulky” or “fat” interface. Reasons to Follow the Interface Segregation Principle