Add "virtual" and "override" keywords for methods

I know that my suggestion (as what you see above in the title) is something (not a must)……Well, however, it would be nice if we can use this "syntax suger" to make TypeScript "more professional", the wrapper of js. Those without the "virtual" cannot be overridden. And when you type something like "override", it will offer you functions that can be overridden.

Thanks anyway!

[RyanCavanaugh]

This would be a breaking change as methods are 'virtual' by default.

it's not even clear what a non-virtual method would mean in JavaScript - there is no such thing as a non-virtual call.

@RyanCavanaugh:

Well, I've changed my topic into a new section:)

In my mind, TypeScript is a nice skeleton that will force us to write js in a strongly-typed language. So my "virtual" and "override" is just "syntax suger" (at Visual Studio's compliation level) to force clients that some methods inherited from the father class has been overridden, this will make us see clearly what methods have been overridden.

In default, all the public methods are automatically marked "virtual" in default, at some very specific situation, we don't wanna our customers to override some methods but the method is still "public", so I used to think a way that we can cancel adding "virtual" onto the method to mark that the method cannot be overridden.

In another word, this intellisense is really a "breaking change" to be offered to clients, and maybe I can change my suggestion to another one: Can TypeScript add another new key word (something like "sealed" in C#) to mark some public methods cannot be overridden?

Thanks!

[RyanCavanaugh]

Can you un-edit the title and log a new issue to track that suggestion? Thanks!

[ngates87]

this may be a superfluous suggestion, but maybe one idea, for purely syntactic sugar keyword that maybe wouldn't break anything, is just allow you to have the override keyword after a function, to make it clear that is overriding a specific function?

[RyanCavanaugh]

@ngates87 #2000

@ngates87：Yes.
@RyanCavanaugh：Please make my issue open, for #2000 have the same issue.