In state management, the goal is to manage the state of an application in a centralized and organized way.
Here are the main concepts in state management:
- State: The state represents the data or variables that determine a component’s behavior and render information to the user.
- Actions: Actions are events or payloads of information that send data from the application to the store.
- Reducers: Reducers are pure functions that take the previous state and an action as inputs and return a new state. They are used to update the state based on the action.
- Store: The store is a single source of truth for the state of the application. It holds the current state and provides methods to access and update the state, such as
- Dispatch: Dispatch is a method provided by the store that allows you to send an action to the store. The store then updates the state based on the action and reducer.
- Subscription: Subscription is a way to listen for changes to the state in the store.
So, in state management, you first define the initial state of the application. Then, you create actions and reducers to update the state based on the actions. The store holds the state and allows you to dispatch actions to update the state. Finally, you can subscribe to the state to get notified when it changes.
Real Life Examples
Let’s consider a real-life example to understand the concepts of state management.
Suppose you have a refrigerator in your home that you use to store food items. The state of your refrigerator can be defined as the current amount of food items it has.
Now, when you want to add or remove food items from the refrigerator, you perform an action, like opening the refrigerator door, putting or taking out food items, and then closing the door.
A reducer, in this case, can be thought of as a rule that governs how the state of the refrigerator should change when a particular action is performed. For example, the rule could be that when the door of the refrigerator is opened and food items are added, the state of the refrigerator should increase. When the door is opened and food items are taken out, the state of the refrigerator should decrease.
In a similar way, in state management, an action represents an event that occurs in your application, such as a user clicking a button. The state represents the current data or values of your application. The reducer is a function that updates the state based on the action. The updated state is then used to render the UI of your application.
Here are other 5 examples to help you understand state management:
- Shopping Cart: Imagine a shopping cart where you can add or remove items. The initial state of the shopping cart is an empty cart. Whenever you add an item to the cart, an action is dispatched to the store that triggers a change in the state of the cart. This updated state is then passed to the component to render the updated cart.
- Weather App: A weather app can display the current temperature, humidity, and wind speed of a specific city. The state of the app is the current weather information for that city. Whenever the user changes the city, an action is dispatched to the store to trigger a change in the state and the component updates to display the new weather information.
- Todo List: A Todo list is another great example to understand state management. The initial state is an empty list of tasks. When a new task is added, an action is dispatched to add that task to the state and the component updates to display the updated list of tasks.
- Music Player: A music player can have different states like playing, paused, and stopped. The initial state is stopped. When the user clicks the play button, an action is dispatched to change the state to playing and the component updates to display the current state of the player.
- Calculator: A calculator can have different states based on the operations performed. The initial state is 0. When the user performs an operation like addition or subtraction, an action is dispatched to update the state of the calculator and the component updates to display the result.
State Management Libraries
There are many state management libraries available for various programming languages. Some popular ones include:
- Vuex (Vue.js)
- ngRx (Angular)
- Bloc (Flutter)
- Provider (Flutter)
- Scoped Model (Flutter)
- ReSwift (Swift)
- Elm (Elm)
- Unidux (TypeScript)
State management is an essential concept in modern web development that allows for the efficient and organized management of the data and variables used in a web application. There are various state management libraries available, such as Redux, MobX, and React’s context API, each with its own set of benefits and drawbacks. Understanding the basics of state management, such as actions, reducers, and states, is crucial for building scalable and maintainable web applications. Effective state management can greatly improve the overall performance, functionality, and user experience of a web application.