Q371. Which is preferred option with in callback refs and findDOMNode()?
It is preferred to use _callback refs_ over `findDOMNode()` API. Because `findDOMNode()` prevents certain improvements in React in the future. The **legacy** approach of ...
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Q372. Why are String Refs legacy?
If you worked with React before, you might be familiar with an older API where the `ref` attribute is a string, like `ref={'textInput'}`, and the DOM node is accessed as ...
Q373. What are the different phases of component lifecycle?
The component lifecycle has three distinct lifecycle phases: 1. **Mounting:** The component is ready to mount in the browser DOM. This phase covers initialization from `c...
Q374. What are the lifecycle methods of React?
Before React 16.3 - **componentWillMount:** Executed before rendering and is used for App level configuration in your root component. - **componentDidMount:** Executed af...
Q375. How to create props proxy for HOC component?
You can add/edit props passed to the component using _props proxy_ pattern like this: ```jsx harmony function HOC(WrappedComponent) { return class Test extends Component ...
Q376. What is context?
_Context_ provides a way to pass data through the component tree without having to pass props down manually at every level. For example, authenticated users, locale prefe...
Q377. What is the purpose of using super constructor with props argument?
A child class constructor cannot make use of `this` reference until the `super()` method has been called. The same applies to ES6 sub-classes as well. The main reason for...
Q378. How to set state with a dynamic key name?
If you are using ES6 or the Babel transpiler to transform your JSX code then you can accomplish this with _computed property names_. ```javascript handleInputChange(event...
Q379. What would be the common mistake of function being called every time the component renders?
You need to make sure that function is not being called while passing the function as a parameter. ```jsx harmony render() { // Wrong: handleClick is called instead of pa...
Q380. What are error boundaries in React v16?
**Note:** Error boundaries were introduced in React 16 and remain valid in current React versions (18/19). _Error boundaries_ are components that catch JavaScript errors ...