![]() ![]() Next, we imported the Movie component and a function fetchMovie from actions. In the code above, we are importing connect from react-redux which is used to connect a React component to the Redux store, provides the component with information from the store and also provides functions used to dispatch actions to the store. The example above returns a value based on the inputs, if you pass 2 and 5 then you’d always get 7, as long as it’s the same input nothing else affects the output you get, that’s an example of a pure function.īelow is an example of a reducer function that takes in a state and an action. Pure functions are functions that do not have any side effects and will return the same results if the same arguments are passed in.īelow is an example of a pure function: const add = (x, y) => x + y For example, an authentication reducer can take an initial state of an application in form of an empty object and an action that tells it that a user has logged in and returned a new application state with a logged-in user. What Is A ReducerĪ Reducer is a pure function that takes the state of an application and action as arguments and returns a new state. We’ll be writing code demos and an application to better understand Reducers and how it affects the state in an application. At the end of the tutorial, you should have a better understanding of the role Reducers play in Redux. An understanding of React and Redux would be beneficial. This tutorial is for developers who want to learn more about Redux Reducers. It is an integral part of the Redux library. Reducers provide a way to update an application’s state using an action. In order to understand and better use Redux, a solid understanding of reducers is essential. In this tutorial, we’re going to learn the concept of reducers and how they work, specifically in React applications. This tutorial will explain the concept of reducers and how they work specifically in Redux. Actions are a plain JavaScript object that describe what changed, sending data from the application to the store.Įxport function reducer(state = '', action) from '.If you have used Redux at any point while developing an application to manage state, you will most definitely have come across reducers. In order to modify state in Redux, actions have to be dispatched. As a plus, a single state tree enables us to debug our application with ease. Visualize the state as a “model”,īut without setters. The whole state of the application is stored in an object tree (within a single store). The official documentation is pretty straightforward and also plenty of examples and nice analogies can be found on the internet. Took the ideas that Flux brought in, leaving out its complexity by “borrowing” things from Elm.įor starters, there are several key concepts to understand: store, actions / action creators, and reducers. It’s a lightweight implementation of Flux, which is another library for managing the state. Redux, according to the offical docs, is a predictable state container for JavaScript apps written byĭan Abramov. ![]()
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