Q2391. How do you capture browser back button?
The `beforeunload` event is triggered when the window, the document and its resources are about to be unloaded. This event is helpful to warn users about losing the curre...
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Q2392. What is the purpose of `getSnapshotBeforeUpdate()` lifecycle method?
The new `getSnapshotBeforeUpdate()` lifecycle method is called right before DOM updates. The return value from this method will be passed as the third parameter to `compo...
Q2393. How do you disable right click in the web page?
The right click on the page can be disabled by returning false from the `oncontextmenu` attribute on the body element. ```html ```
Q2394. What is the recommended way for naming components?
It is recommended to name the component by reference instead of using `displayName`. Using `displayName` for naming component: ```javascript export default React.createCl...
Q2395. What are wrapper objects?
Primitive Values like string,number and boolean don't have properties and methods but they are temporarily converted or coerced to an object(Wrapper object) when you try ...
Q2396. What is the recommended ordering of methods in component class?
_Recommended_ ordering of methods from _mounting_ to _render stage_: 1. `static` methods 2. `constructor()` 3. `getChildContext()` 4. `componentWillMount()` 5. `component...
Q2397. What is AJAX?
AJAX stands for Asynchronous JavaScript and XML and it is a group of related technologies(HTML, CSS, JavaScript, XMLHttpRequest API etc) used to display data asynchronous...
Q2398. Why we need to pass a function to setState()?
The reason behind for this is that `setState()` is an asynchronous operation. React batches state changes for performance reasons, so the state may not change immediately...
Q2399. What are the different ways to deal with Asynchronous Code?
Below are the list of different ways to deal with Asynchronous code. 1. Callbacks 2. Promises 3. Async/await 4. Third-party libraries such as async.js,bluebird etc
Q2400. Why is `isMounted()` an anti-pattern and what is the proper solution?
The primary use case for `isMounted()` is to avoid calling `setState()` after a component has been unmounted, because it will emit a warning. ```javascript if (this.isMou...