React MobX not triggering rerender on props change

Question

I'm new to MobX and I am having some issues calling async actions. My store has a async function for updating an observabel array:

export class AccountStore implements IAccountStore {
@observable accounts:any = [];
@observable state = "pending"; // "pending" / "done" / "error"

@action
public async getAccounts() {
    this.state = "pending"
    try {
        const res = await accountsService.getAll();
        runInAction(() => {
            console.log(res);
            this.state = "done";
            this.accounts.replace(res.data);
        })
    } catch (error) {
        runInAction(() => {
            this.state = error;
        })
    }
}

}

But my component does not rerender on update (which is called on componentDidMount):

interface AppProps {
accountStore: IAccountStore
}

@inject('accountStore')
@observer
class AllAcounts extends Component<AppProps, any> {
constructor(props: any) {
    super(props);
}

public componentDidMount() {
    this.props.accountStore.getAccounts();
    console.log(this.props.accountStore)
}

render() {
    const accounts = this.props.accountStore.accounts;
    return (
        <div>
            <h4>All accounts</h4>
            {accounts.map((item: any, index: number) => {
                <p key={index}>{item.name}</p>
            })
            }
            <button onClick={() => this.props.accountStore.getAccounts()}>Update</button>
        </div>
    );
}
}

export default AllAcounts;

I can see the props are getting updated when i use the React inspector in Chrome.

Any suggestions to where I am going wrong?

Answer 1

You are not returning anything from the the function given to map in the render method of your component. Add the return keyword and it will work as expected.

{accounts.map((item, index) => {
  return <p key={index}>{item.name}</p>;
})}