May 30th is the 10th anniversary of React . I pulled React the latest code, and it doesn't matter. There are already 22 hook . where: react package exports 21 react-dom package exports 1 ( useFormStatus ) this article will talk about the role of React from the perspective of the development of hook over the years. the change of times up to now, the development of React has mainly gone through three periods: CSR period (client rendering period) concurrent period RSC period (server component period) the current 22 hook are also the products of these three periods. CSR period back in 2013, in order to solve the increasingly complex interactions of facebook , jordwalke developed React . After a period of exploration, React gradually formed a set of development mode that satisfies CSR . this development model migrates from ClassComponent to FunctionComponent , resulting in the first batch of hook . These hook are all related to the development mode of CSR . For example: related to the flow of states: useState useReducer useContext related to side effects of treatment: useEffect useLayoutEffect related to improving the degree of freedom of operation: useRef related to performance optimization: useMemo useCallback related to debugging: useDebugValue with the continuous iteration of React , several hook are introduced. In essence, they all aim to improve the development model of CSR and supplement or restrict the existing hook capabilities: useImperativeHandle (control useRef to prevent it from getting out of control) useEffectEvent (a supplement to useEffect capabilities) useInsertionEffect (supplement to useEffect scenarios) useMemoCache (reduce the mental…

in the article React developer essential skills: master useReducer foundation and application , we discussed the basic knowledge of useReducer in React. In this article, we will discuss the advanced techniques of useReducer. This article will show you how to flexibly use useReducer to manage complex states within and between components in React programs through a more complex "task control component"-- the core operation component of task processing in TODO applications. implementation ideas in TODO applications, the core operation is the various processing logic of "task", including "add task", "delete task", "filter task", "search task" and so on. To make it easier to understand, we only implement the "add task" and "delete task" logic. at the same time, in order to facilitate us to later maintain and expand the function and logic of the "task" operation, we should package it into a separate component. In addition, the "add task" and "delete task" functions of the component should also be exposed for the parent component to call. subcomponents TaskControl this subcomponent should contain the following functions: use useReducer in the component to manage the task list and use useRef to create a reference to get the value of the input box. wraps the component with forwardRef so that the add task and delete task methods in the component can be called from the parent component. defines functions for add tasks and Delete tasks to update the task list. use useImperativeHandle to expose the add task and delete task functions to the parent component for calling. Let's take a look at the…

in React, the management of component state is very important. Typically, we can use useState to manage component state. However, using useState can become very tedious if the state becomes more and more complex. At this point, we can consider using useReducer to manage the state. you might ask, why not use Redux? It is true that Redux is an excellent and popular state management tool, but there are some scenarios where Redux is not the optimal solution. For example, our application is very small, and using Redux at this time may bring additional complexity. Another example is to update the status frequently, which may cause a large number of action to be triggered, which adds additional overhead and complexity. Therefore, for similar scenarios, useReducer might be more appropriate. so how do we correctly apply useReducer ? This article will give you the answer. what is useReducer useReducer is a hook function used to manage the state of components in React. Its function is to decompose the state of the component into multiple values, and to provide a predictable and controllable way to update the state, thus making the code clearer and easier to understand. useReducer is defined as follows: const [state, dispatch] = useReducer(reducer, initialState); useReducer accepts two parameters: reducer : a function that accepts the current state and action (action) , returns the new state . In reducer , you can modify the state according to the type of action . initialState : the initial value of the state. useReducer & the return value of nbsp; is an…

Hello, everyone. I'm Carson. The code volume of React can be said to be quite large. Is there a function in such a large library that is not mentioned in the document but actually exists ? the answer is yes. this article will introduce you to hidden egg features that are not mentioned in three documents. ref cleanup in the current React , Ref has two data structures: <T>(instance: T) => void {current: T} for most requirements, we will use the second data structure. It is also the data structure returned by useRef and createRef . the first data structure is mainly used for DOM monitoring. For example, in the following example, the size of div is reflected in the height state: function MeasureExample() { const [height, setHeight] = useState(0); const measuredRef = useCallback(node => { if (node !== null) { setHeight(node.getBoundingClientRect().height); } }, []); return ( <div ref={measuredRef}>Hello Kasong</div> ); } but in the above example, the size change of DOM cannot be reflected in real time to the height state. To reflect real-time changes, you need to use native API that monitors DOM , such as ResizeObserver , monitor DOM size change IntersectionObserver , monitor DOM visual area changes MutationObserver , monitor DOM tree changes these API are usually event-driven, which involves unbinding events when monitoring is not needed. since event binding occurs in the ref callback, naturally, unbinding events should also occur in the ref callback. For example, modify the above example with ResizeObserver : function MeasureExample() { const [entry, setEntry] = useState(); const measuredRef = useCallback((node)…