How to check if members are initiated in constructor

[demiculus]

Here is the full question https://stackoverflow.com/questions/66646134/checking-if-members-are-initiated-yet-in-constructor

 

I have a class that extends `PIXI.Text` which overrides the default `this.text` with something like so: 

```
    set text(newText: string) {
        super.text = newText
        this.updateToolTipText(newText)
    }
```

The problem is that:

1. `set text` gets called during the construction of the class
2.  and `this.udpateToolTipText()` uses `this.width` to adjust the container size

BUT when called during the construction of the class, `this.width` isn't defined yet and throws this error: 

`TypeError: null is not an object (evaluating 'style.styleID')`

I've tried `if(this.width == undefined) return` and `if(this.width == null) return` but nothing seems to prevent this error from triggering. After construction is complete, the class behaves as expected, this is only being thrown during construction.

I've hacked around this solution by creating a dummy variable to return out during construction but I just don't understand how/why I can't check if `this.width` exists without throwing the error. 
 

[ivan.popelyshev]

set text(newText: string) {
        super.text = newText

Are you sure super setters can even work in javascript/typescript?

> `set text` gets called during the construction of the class

if (!this.ready) {
   ...
}

in the end of overriden constructor: ready= true;

as to WHY? question: its OOP, it has problems in all libs /frameworks.

I really dont want to explain the sequence of how pixi initiates it because it can change later. If you want to alter this behaviour, just post issue or even PR in pixijs github. If you want to know WHY? - read the source code, because its the usual OOP initialization bullshit.
 

Edited March 16, 2021 by ivan.popelyshev