Vanilla State Manager

Overview

Vanilla State Manager is a lightweight, type-safe state management solution for JavaScript applications. It provides a simple and intuitive API for managing state, handling updates, and notifying listeners.

Installation

To install Vanilla State Manager, run one of the following commands:

npm install vanilla-state-manager

yarn add vanilla-state-manager

pnpm install vanilla-state-manager

Usage

Here's an example of how to use Vanilla State Manager:

import StateManager from "vanilla-state-manager";

// Create a new state manager with an initial state
const initialState = { count: 0 };
const stateManager = new StateManager(initialState);

// Get the current state
const currentState = stateManager.getState();
console.log(currentState); // Output: { count: 0 }

// Update the state using the setState method
stateManager.setState((draft) => {
  draft.count += 1;
});
console.log(stateManager.getState()); // Output: { count: 1 }

// Subscribe to state changes using the subscribe method
const unsubscribe = stateManager.subscribe((state) => {
  console.log(state);
});
stateManager.setState((draft) => {
  draft.count += 1;
}); // Output: { count: 2 }
unsubscribe();

API

StateManager<T>

• constructor(initialState: T): Creates a new state manager with the given initial state.
• getState(): T: Returns the current state.
• setState(updater: (draft: T) => void): void: Updates the state using the provided updater function.
• subscribe(listener: Listener<T>): () => void: Subscribes to state changes using the provided listener function.

Listener<T>

• (state: T) => void: A function that will be called whenever the state changes.

Types

• T: The type of the state.

Errors

• State cannot be null or undefined: Thrown when the initial state is null or undefined.
• Updater function cannot be null or undefined: Thrown when the updater function is null or undefined.
• Listener function cannot be null or undefined: Thrown when the listener function is null or undefined.

Dependencies

• immer: Used for state immutability.

License

Vanilla State Manager is licensed under the MIT License.

TypeScript

Usage

Here's an example of how to use Vanilla State Manager with TypeScript:

import StateManager from "vanilla-state-manager";

// Create a new state manager with an initial state
interface State {
  count: number;
}

const initialState: State = { count: 0 };
const stateManager = new StateManager(initialState);

// Get the current state
const currentState: State = stateManager.getState();
console.log(currentState); // Output: { count: 0 }

// Update the state using the setState method
stateManager.setState((draft: State) => {
  draft.count += 1;
});
console.log(stateManager.getState()); // Output: { count: 1 }

// Subscribe to state changes using the subscribe method
const unsubscribe = stateManager.subscribe((state: State) => {
  console.log(state);
});
stateManager.setState((draft: State) => {
  draft.count += 1;
}); // Output: { count: 2 }
unsubscribe();

Type Definitions

The StateManager class is generic, so you can specify the type of the state when creating a new instance. The getState and setState methods will then return and accept the specified type, respectively.

The Listener type is also generic, so you can specify the type of the state when creating a new listener. The listener function will then receive the specified type as an argument.

Note that the immer package is already included in the vanilla-state-manager package, so you don't need to install it separately.