View Models and Separating Business Logic from UI

In software development, a view model is an architectural pattern that separates the presentation layer (UI) from the business logic layer.

Getting Started

Installation

npm i @xeinebiu/react-mvvm@2.0.7

Creating a ViewModel

To create a new view model, extend the ViewModel class provided by this library:

import { createViewModel } from '@xeinebiu/react-mvvm';

const counterViewModel = createViewModel({ counter: 0 }, viewModel => ({
    increment: () =>
        viewModel.setState({ counter: viewModel.getState().counter + 1 }),
    decrement: () =>
        viewModel.setState({ counter: viewModel.getState().counter - 1 }),
}));

Using useSelector Hook

The useSelector hook allows you to subscribe to changes in the view model state and efficiently update your components:

import { useSelector } from '@xeinebiu/react-mvvm';

function CounterComponent() {
    const count = useSelector(counterViewModel, vm => vm.getState().count);

    return (
        <div>
            <p>Count: {count}</p>
            <button onClick={counterViewModel.increment}>Increment</button>
            <button onClick={counterViewModel.decrement}>Decrement</button>
        </div>
    );
}

In this example, the CounterComponent will automatically re-render whenever the count state in the CounterViewModel changes.

API

ViewModel

Method	Description
constructor(initialState: T)	Creates a new instance of ViewModel with the provided initial state.
getState(): T	Returns the current state of the ViewModel.
setState(newState: Partial<T>): void	Updates the state of the ViewModel with the provided partial state object.
subscribe(listener: Listener<T>): () => void	Subscribes a listener function to be called whenever the state of the ViewModel changes. Returns an unsubscribe function.
dispose(): void	Clears all listeners and disposes of the ViewModel.

useSelector

(viewModel: T, selector: (viewModel: T) => S): S

A hook that subscribes to changes in the ViewModel's state and efficiently updates the component when the selected state changes.

License

This library is licensed under the MIT License.