Lorese

Lorese is a really lightweight state manager for frontend applications. It uses a single store for caching the data, and it should considered the source of truth for your app.

It is compound by 3 main parts:

• LO - loaders: Allow to fetch data asynchronously, and returns an object that can be consumed directly in a declarative way.
• RE - reducers: Set the data in the store, updating the cache and emiting events to allow you refresh your UI.
• SE - selectors: Create selectors to access the data in the store. Best practice is not to allow your UI get the store directly, instead create selectors with logic reusable across your app.

How to use it

import Lorese from 'lorese';

// We will have a store with 2 attributes
const store = {
  todoIds: null, // This will be a list with our todo's ids
  todos: {} // A map with the todos indexed by id
}

// Create our state manager
const stateManager = Lorese(store);

// We can access to the 3 elements from our stateManager
const {loader, selector, reducer} = stateManager;

// Selectors will give sense to our store
const getTodos = selector( store => {
  // If our todos aren't loaded just return
  if( !store.todoIds ) return;

  // Return our todo's
  return store.todoIds.map( id => store.todos[id] );
})

// Use a reducer to update our store
const onTodosLoaded = reducer( (store, todoList) => {
  let todoIds = [];
  let todos = {...store.todos};
  todoList.forEach( todo => {
    ids.push(todo.id);
    todos[todo.id] = todo;
  })

  // Return the store updated
  return { todoIds, todos };
});

// Create a loader to fetch our todos
const loadTodos = stateManager.loader({
  selector: getTodos, // if the selector returns undefined, the load() method

  async load(){
    let todoList = await api.fetchTodos();
    // Using the reducer here will update the store and refresh the UI
    onTodosLoaded( todoList );
  }
})

// ...
// Within your UI you can use the loader declaratively
const {isLoading, data: todos} = loadTodos();
isLoading ? renderLoading() : renderTodos(todos);

Subscribe to changes in the store

// Once the stateManager is created...
const stateManager = Lorese(store);

// We should have a method to refresh our UI
function rerender(){ /* Refresh our UI */ }

// We can listen to changes in the store
stateManager.addChangeListener( rerender );

// We can stop listening to the changes
stateManager.removeChangeListener( rerender );