![]() ![]() The React useContext hook allows you to access this context object and retrieve the necessary data. It lets you easily share state in your applications. A context provider is a component that provides data to all of its children via a context object. React context is an essential tool for every React developer to know. See example codepen.Ĭheck out this great example on dev. The useContext hook is a built-in hook in React that allows you to consume data from a context provider. The object structure that you're providing the context provider is invalid. When using state with your Provider, you need to return as proper JSON to the provider, so that that it can subscribe to value changes, and notify its descendants The structure of data provided as the value to provider This gives an object structure that React can't properly subscribe to and listen for changes. Within your example, you return the result of the useState call as-is to your context provider. In other words, React’s Context API is there to solve a simple problem. Returning the result of useState as the provider value Context API According to the official documentation, Context API provides a way to pass data through the component tree without having to pass props down manually at each level. This is what the process involves: Create a context object by using React. It's for this reason you want to treat your providers/context objects as pure functions where possible. useContext () can prove to be a simple alternative to other state management libraries if your data is not complicated and the application is small. There are rules around this, precedence and delays, but you are guaranteed a re-render of whatever Functional Component consumes the useState hook. useState however, is a react Functional Component Hook that will trigger a new render every time the value is updated. React is very good at determining what to re-render and when, and it provides you with control to limit that behavour even more. In a typical React application, data is passed top-down (parent to child) via props, but this can be difficult for certain types of props (e.g. When consuming the result of useState within a react Context, you have to be aware of the implications of consumption in descendants, and the impact that it will have. The structure of data provided as the value to provider.Returning the result of useState as the provider value, and.There are several things in your code that need to be addressed: The provider itself is not a hook, therefore when using hooks to generate values, you must re-render the provider with the new values set. There are a few caveats to remember - whenever the properties of the value your provider is changing, it will trigger a re-render in all of its subscribers - it's descendants. The use of createContext creates a reference for a data structure within React's ecosystem that exposes a given data structure to the children nodes.Ĭontext.Provider on the other hand provides a value to consuming components that are children nodes of the Provider. The React Context is a mechanism for passing data through a React node tree without having to pass the props manually. ![]()
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