Q721. What happens if we add two arrays?
If you add two arrays together, it will convert them both to strings and concatenate them. For example, the result of adding arrays would be as below, ```javascript conso...
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Q722. What are forward refs?
_Ref forwarding_ is a feature that lets some components take a _ref_ they receive, and pass it further down to a child. ```jsx harmony const ButtonElement = React.forward...
Q723. What is the output of prepend additive operator on falsy values?
If you prepend the additive(+) operator on falsy values(null, undefined, NaN, false, ""), the falsy value converts to a number value zero. Let's display them on browser c...
Q724. 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 ...
Q725. How do you create self string using special characters?
The self string can be formed with the combination of `[]()!+` characters. You need to remember the below conventions to achieve this pattern. 1. Since Arrays are truthfu...
Q726. 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 ...
Q727. How do you remove falsy values from an array?
You can apply the filter method on the array by passing Boolean as a parameter. This way it removes all falsy values(0, undefined, null, false and "") from the array. ```...
Q728. 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...
Q729. How do you get unique values of an array?
You can get unique values of an array with the combination of `Set` and rest expression/spread(...) syntax. ```javascript console.log([...new Set([1, 2, 4, 4, 3])]); // [...
Q730. 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...