In this article, we are going to see how to debug the custom hooks with the useDebugValue hook in ReactJS.This hook provides custom labels to custom hooks so as to make the process of debugging easier and efficient. It is only called when the React Developer tools are toggled on.SyntaxuseDebugValue(value, ()=>{})ParametersValue − Label for the custom hook.()=>{} − Function to format the label.ExampleIn this example, we will build a React application that displays a custom label for the custom hook of our React application.App.jsxfunction useCustomHook(val) {    const [value, setValue] = useState(null);    useDebugValue(value ? Not Empty : Empty);   ... Read More

In this article, we are going to see how to access the data without passing it through every parent component in the React Lifecycle.This hook is the better replacement of the Context API of the Class-based component which is used to set the global data and this data can now be accessed in any of the children components without the need to pass it through every parent Component.Syntaxconst authContext = useContext(initialValue);The useContext accepts the value provided by React.createContext and then re-render the component whenever its value changes but you can still optimize its performance by using memoization.ExampleIn this example, we ... Read More

In this article, we are going to see how to optimize a React application by passing a memoized function.This hook is used to optimize a React application by returning a memoized function which helps to prevent unnecessary re-rendering of a function. This hook stores the cached value of the function and only updates the function if the passed dependencies changes.Syntaxconst memoizedCallback = useCallback(() => {doSomething(a, b); }, [a, b], );Here, doSomething() function will only be called again on the next re-render if the values of a or b changes; otherwise only the cached version of the function is passed.Note: useCallback(fn, ... Read More

In this article, we are going to see how to increase the performance of React application by rerendering the component only when the props passed to it changes or on when certain conditions are met.This method is majorly used to take an exit from the complex React lifecycle, but using it extensively may lead to bugs in the application.SyntaxshouldComponentUpdate(nextProps, nextState)By default, the return value of this method is true; but if it returns false, then the render(), componentWillUpdate() and componentDidUpdate() methods are not called.Example 1In this example, we will build a React application with components only getting re-rendered if the ... Read More

In this article, we are going to see how to execute a function after the component is updated and before rendering it to the DOM.This method is called before the rendering of the component and after it is updated. This method is majorly used to compare the previous state or the previous props of the component with the new state or the new received props. The value returned by this method is passed as an argument to the componentDidUpdate method.SyntaxgetSnapshotBeforeUpdate(prevProps, prevState)ParametersprevProps − Previous props passed to componentprevState − Previous state of componentExampleIn this example, we will build a React application which ... Read More

In this article, we are going to see how to execute a function before the component is rendered.This method is called before the rendering or before any updation of the component. This method is majorly used to update the state, before the rendering of the component, which depends upon the props received by the component. This method is called on every rerendering of the component.Syntaxstatic getDerivedStateFromProps(props, state)Parametersprops − Props passed to componentstate − Previous state of componentExampleIn this example, we will build a React application which will fetch the list of users and on clicking the 'fetch user' button, the ... Read More

In this article, we are going to see how to execute a function if some error occurs in the component.This method is called when a component encounters some error during the React Component Lifecycle. This method allows us to handle the error boundaries of the application. To avoid performance issues, don’t set up any side-effects in this method.Syntaxstatic getDerivedStateFromError(error)It accepts the error as a parameter that was thrown as a component.ExampleIn this example, we will build a React application that displays the contained Comp1 component if no error occurs; otherwise it displays some text. But here, in Comp1 component, error ... Read More

In this article, we are going to see how to execute a function by forcibly re-rendering a component.The component in the React lifecycle only re-renders if the props passed to it or its state changes but to forcibly render the component, use the build it forceUpdate method. This method overrides the shouldComponentUpdate method defined in the component but will consider the shouldComponentUpdate method defined in the children component.Syntaxcomponent.forceUpdate(callback)ExampleIn this example, we will build a React application that gets forcibly re-rendered on a button click.App.jsximport React from 'react'; class App extends React.Component {    update = () => {   ... Read More

While building a React application, the most-used Chrome extension for debugging the React application or to solve the error is React Developer Tools which is a free-to-use and opensource chrome extension.This extension is used to navigate through the nested component tree of the React Components. It takes a lookup into the stored state and the props values and also records the performance information.Note: This extension also tells whether a page is using the technology stack of ReactJS or not.How to installGo to Chrome web store and install React Developer Tools.When you tap on this extension, it will show if the ... Read More

In this article, we are going to see how to create a reference to any DOM element in the functional component.This method is used to access any DOM element in a component and it returns a mutable ref object which will be persisted as long as the component is placed in the DOM. If we pass a ref object to any DOM element, then the. current property to the corresponding DOM node elements will be added whenever the node changes.SyntaxReact.createRef()ExampleIn this example, we will build a React application that will pass the ref object to two input fields and when ... Read More