This works, but what if you need to call a context method earlier (such as in a componentDidUpdate)? Setting up a higher order component allows you to access context anywhere in the component, not just in the return. Most other tutorials have you use the consumer to wrap inside the render() method of a component. There are tons of different ways to set Context API up. You can fork, clone, then run it by typing npm start in the terminal once inside the project.
React multiple contexts code#
If you haven’t been typing your own example along the way and want to see this in action for yourself, head to This is a repo with a working example of all the code above. As we discussed before, this is how context is added to props. Keep in mind – you need to wrap each component that uses context with your higher order component: withContext(). This should log the object you passed from ContextProvider.js:Įxport default withContext(SomeComponent) Import withContext from 'path/to/Context_HOC' Here’s an example of a stateless component using context to display dynamic data: This grants the created context to and all of its children.Ĭontext API is now completely set up and ready to use in any component that you wish. Import ContextProvider from './ContextAPI/ContextProvider' If you’re using create-react-app, head into your index.js file and modify it like this: Still reading? You’re a champion! There’s only one more setup step required – the whole rendered app needs to be wrapped with. Let’s start coding!Įxport const AppContext = React.createContext()Įxport default class ContextProvider extends React.Component. This is, in essence, a regular stateful React component – so it should look pretty familiar as we build it out. Navigate to the desired location and create a new folder with an obvious name (example: ‘ContextAPI’).Ĭreate a file called ContextProvider.js inside of your Context API folder. If you’re using create-react-app, the best place for it is inside the pre-built src folder. You may find that you prefer Context API for this very reason!Ĭhoose where your Context API files should live in your project’s directory. The main differences will be infrastructural – Context API doesn’t use action handlers, payloads, or a reducer state. If you have experience with Redux, a lot of the concepts shown here will be familiar. Instead we shall make a singular global data sharing system, much like how Redux functions. However, this tutorial will not cover creating various specialized contexts. It’s important to note that React Context API allows you to build multiple contexts and apply them to specific component trees.
React multiple contexts how to#
This article is meant to provide an alternative, detailed guide on how to enable React Context API through the use of a higher order component. That being said, the instructions and examples React provides can be confusing to some people. Looking through the official documentation on Context API is helpful, and you may want to refer to them alongside this article when working with it for the first time or two ( click for React’s docs). If this sounds awesome to you, keep reading to learn how to apply it in your projects! Using Context API doesn’t add any dependencies, doesn’t require middleware or packages for HTTP requests, and is usually quicker to set up. While Redux works well and remains the most common solution, React recently introduced a built-in alternative called Context API. Global state management is an important tool for any React project larger than a few components or routes. Step 3: Create the higher order consumer component.This article is a step-by-step process on how to set up global state with Context API, and how to use it with a higher order component. This article is meant for a more technical audience. Michael Kerr is a web developer and development mentor at Devmountain. This function takes a optional parameter which is the default value.Accessing React’s Context API Through a Higher Order Component
![react multiple contexts react multiple contexts](https://i.morioh.com/2019/10/24/ef148921fc61.jpg)
In the first step we create a context using the createContext(default) function. Using the Context API in React is a 3 Step Process. This solves the problem of Props drilling. Using Context you can maintain a central state and pass it in the form of props and extract it in the components where you need. You can read about Redux in my other blog here. Both are used for Central state management. Context API is a simple alternative to Redux library. React Context readily makes data available to the components without manually passing it through the entire component tree. useContext() hook belong to the Context API which is used for state management in React. React’s useContext() hooks makes passing data from Parent Component and consuming it in a child component easy. Passing data down the Multiple layers of components in React is a tough.