There is a class First and constructor function Second. I'm trying to create a class Both as a child of both of them. More accurate, I'm copiing methods from constructor function prototype to child class prototype.
I do understand that it's not the real inheritance, but that's enough for me.
There is other problem. How can I make typescript to accept copied methods?
class First {
someMethod() {
console.log('someMethod from First');
}
}
function Second() {
console.log('Second');
}
Second.prototype.doSmth = function () {
console.log('doSmth from Second');
}
interface IBoth {
someMethod()
doSmth()
}
class Both extends First /* implements IBoth */ {
constructor() {
console.log('constructor of Both');
super();
Second.call(this);
}
}
for (let key in Second.prototype) {
Both.prototype[key] = Second.prototype[key];
}
In fact I need to see the metods one level deepper:
class Final extends Both {
doIt() {
this.someMethod();
//this.doSmth(); // How to make this call threated as correct?
(this as any as IBoth).doSmth(); // That compiles, but it's awfull
}
}
if in this case methods won't be visible in class Both, it's ok.
I've already tryed:
When writing
class Both extends First implements IBoth {
typesctipt says that I haven't implement interface methods.
Renaming Both to _Both and using
var Both = _Both as typeof _Both;
leaves same problems as original code, as First is never mentoned.
If I rename Both to _Both and write
var Both = _Both as typeof IBoth;
typescript can't find IBoth.
Are there some other ways to reach it?
You can try at http://www.typescriptlang.org/Playground
Full code there
Add this line and run the code (copy code from right panel to your browser console):
(new Final).doIt();
Output when line this.doSmth(); is not commented:
constructor of Both
Second
someMethod from First
doSmth from Second
doSmth from Second
Try this:
class Both extends First {
constructor() {...}
doSmth: typeof Second.prototype.doSmth;
}
It's also better to have Second as a class instead of a function. Add a declaration file if that's a javascript module.
Lastly, and if you can't have types for Second, just add types for each function like this:
class Both extends First {
constructor() {...}
doSmth: () => void;
}
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