5.4 Cannot read property 'enumerable' of undefined

[timothyallan]

Hey all, ViewModel is 5.4 is lighting up my console with waaaay too much red text!

My class objects which I'm using as ViewModels have the usual observable properties, but occasional functions as well.

It seems like this is the culprit

mobx-utils/src/create-view-model.ts

Line 59 in 5d147c1

const { enumerable } = Object.getOwnPropertyDescriptor(model, key)

In this loop,

mobx-utils/src/create-view-model.ts

Line 46 in 5d147c1

getAllMethodsAndProperties(model).forEach((key: any) => {

As soon as the key is the name of a function in my class object, I get Uncaught TypeError: Cannot read property 'enumerable' of undefined

and everything explodes. 5.2 works great.

[ItamarShDev]

9aebd22

[ItamarShDev]

@timothyallan can you please provide a codesandbox example?

[timothyallan]

Sure, it won't let me save it, but simply paste this into the index.js and it crashes.

import React from "react";
import { render } from "react-dom";
import { observable, action } from "mobx";
import { observer } from "mobx-react";
import DevTools from "mobx-react-devtools";
import { createViewModel } from 'mobx-utils';

class MyClass {
  @observable firstname;
  @observable lastname;

  someFunction(someParam) {

  }
}

class AppState {
  constructor() {
    const myClass = new MyClass();
    const observableMyClass = createViewModel(myClass);
  }

  @action.bound
  reset() {
    this.timer = 0;
  }
}

const TimerView = observer(({ appState }) => (
  <button onClick={appState.reset}>Seconds passed: {appState.timer}</button>
));


render(
  <div>
    <TimerView appState={new AppState()} />
    <DevTools />
  </div>,
  document.getElementById("root")
);

[ItamarShDev]

Using arrow function seems to work, like someFunction = (someParam) => {}
I am not saying its what should happen, but give my take

your thoughts @mweststrate ?

[mweststrate]

the arrow function "fixes" it as that makes the method a local (own) property, which is present indeed.

I think a simple fix (strictly speaking not 100% correct) would be:

const descriptor = Object.getOwnPropertyDescriptor(model, key)
const enumerable = descriptor ? !!descriptor.enumerable : false

[dr0p]

Please review this fix #198
Sorry for the miss..

[timothyallan]

This seems fixed now in 5.4.1. Thanks!