Cannot extend class using Typescript

Question

I'm trying to extend a class that exists as a node_module.

My extended class has no access to the parent's prototype.

Here's a link to a repro:

https://bitbucket.org/IamHttP/repro-types/src/master/

Here's an image that shows this behaviour in WebStorm

As you can see, one has access to destroy() and one does not.

Did you run it to check if it is weird behavior of WebStorm ? — zken
– zken, Commented Feb 21, 2020 at 15:39
yea ofcourse :) typescript itself is not compiling even from the command line. — Patrick
– Patrick, Commented Feb 21, 2020 at 20:05
Do you think you could reproduce this in a web IDE so that people who want to help can do so without npm installing code on their machines? Also, as mentioned in How to Ask, it's a good idea that any minimal reproducible example example be included as text in your question, not only as an external link or as a picture. Thanks! — jcalz
– jcalz, Commented Feb 22, 2020 at 2:28
Thanks for hte input @jcalz - I was sure the issue is related to a node module, so I guess I had to provide a real example with a node_module. I'll take note for future questions. I tried to be as informative as possible :) — Patrick
– Patrick, Commented Feb 22, 2020 at 9:28

Josh Wulf · Accepted Answer · 2020-02-23 01:23:22Z

3

Your type definition for Entity is not properly exported from the first package. Use Go to Definition on game-platform in your second project and you'll see this in your first package's types:

import Entity from 'lib/ECS/Entity';
import entityLoop from 'lib/ECS/util/entityLoop';
import ObjectPool from 'lib/ObjectPool/ObjectPool';
import GameCanvas from 'lib/GameCanvas/GameCanvas';
import Engine from 'lib/Engine/Engine';
...

It is typed as any on import in the consuming project, because that path cannot be resolved. Changing it to this in the first package makes it work as expected:

import Entity from './lib/ECS/Entity';

edited Feb 23, 2020 at 1:23

answered Feb 22, 2020 at 2:56

Josh Wulf

4,9122 gold badges24 silver badges35 bronze badges

Sign up to request clarification or add additional context in comments.

3 Comments

Evert Over a year ago

Wow good find. I also took a look. Looks like this might be a good idea to add a stricter configuration. My typescript will warn me on bad exports and imports that don't have types.

Josh Wulf Over a year ago

No implicit any might do it. You can use eslint to disallow any at all.

Patrick Over a year ago

Thanks! I started investigating down that path myself, I found a closed issue with typescript that it does not re-write the import paths in generated files - this is really unfortunate as I'd like to use alias paths in my projects instead of ../../../../../ hell - Much appreciated @JoshWulf

Roberto Zvjerković · Accepted Answer · 2020-02-21 16:49:16Z

0

destroy method is probably private.

class A {
  private a;
  constructor() {

  }
}

class B extends A {
  constructor() {
    super();
  }
}

const b = new B();
b.a; // Error

answered Feb 21, 2020 at 16:49

Roberto Zvjerković

10.2k4 gold badges31 silver badges49 bronze badges

1 Comment

Patrick Over a year ago

Thanks, but it's not actually private, I control both packages. also, the JS part does work (if compile by force I have access to destroy in real JS code)

Collectives™ on Stack Overflow

Cannot extend class using Typescript

2 Answers 2

3 Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

3 Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related