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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
ExamplesApproach to solve this problemStep 1 − Define a method that accepts the head of a linked list.Step 2 − If head == nil, create a new node and make it head and return it as the new head.Step 3 − When index == 0, then update the head.Step 4 − Iterate the given linked list from its head. Also, initialize preNode that will keep the store address of the previous node.Step 5 − If index i matches with the given index, then then delete that node.next, break the loop.Step 6 − Return, at the end of loop.Example Live Demopackage main ... 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
ExampleApproach to solve this problemStep 1 − Define a method that accepts the head of a linked list.Step 2 − If head == nil, return the head.Step 3 − When index == 0, then return head.nextStep 4 − Else, iterate the given linked list from its head.Step 5 − If index i matches with the given index (to be deleted), then delete that node.next, break the loop.Step 6 − Return, at the end of the loop.Example Live Demopackage main import "fmt" type Node struct { value int next *Node } func NewNode(value int, next *Node) *Node{ var n ... Read More
ExamplesApproach to solve this problemStep 1 − Define a method that accepts the head of a linked list.Step 2 − If head == nil, return the head.Step 3 − When index == 0, then return head.nextStep 4 − Else, iterate the given linked list from its head.Step 5 − If index i matches with the given index (to be deleted), then delete that node.next, break the loop.Step 6 − Return at the end of the loop.Example Live Demopackage main import "fmt" type Node struct { value int next *Node } func NewNode(value int, next *Node) *Node{ var n ... 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
ExampleApproach to solve this problemStep 1 − Define a method that accepts the head of a linked list.Step 2 − If head == nil, return the head.Step 3 − When index == 0, then return head.nextStep 4 − Else, iterate the given linked list from head.Step 5 − If index i matches with the given index (to be deleted), then delete that node.next, break the loop.Step 6 − Return at the end of the loop.Example Live Demopackage main import "fmt" type Node struct { value int next *Node } func NewNode(value int, next *Node) *Node{ var n Node ... 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