Are you planning on becoming a React Hooks professional? Then, this blog is the one for you. With the help of professionals, we have curated certain important questions that will be asked during the interview. Moreover, we assure you that these will help you crack the same with ease.
In conditions, nested functions or loops do not call Hooks. Hooks ought to be employed at the elite level of React functions at all times. This rule makes sure that each time an element renders, Hooks are performed in the same order.
Before we begin the interview questions, for better understanding and grasping, we have divided these questions into categories, namely:
We can wrap components that we don't want to re-render unless the props inside them change with a higher-order component (HOC), called memo().
React Hook Memo() can be used to encapsulate methods inside of a component. This allows us to make sure that only if one of its variables changes do the values inside that function need to be recalculated.
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Data can be easily passed across your project without individually providing props down the ranks thanks to React's useContext hook. To manage the state at the global level, use React Context. Provide the state value and wrap child elements in the context provider.
In order to store the information on behalf of that component instance, hooks utilize a stateful closure all around the invocation of the come equipped. React keeps that closure intact.
A potential continuation of the preceding query, still dealing with the management of data on the inside of a component. Effective use of components in React requires a solid understanding of the concept of state. As the applicant, make careful to describe states and how a React component uses them. A component's local, state-containing information may vary over the course of the component's existence.
In React, context is a mechanism for data sharing. This query may be used by the interviewer to test the applicant's comprehension of the data-passing and data-sharing capabilities of components. The applicant must be able to provide context and articulate their desired use cases. Context is another method for transferring data along the feature tree without explicitly transferring props at each level. Within a component tree, context is intended to exchange info that is deemed "global."
In the majority of applications, conditionally displaying an element is a common requirement. For instance, a component might only need to be presented if a specific set of data is present in the state of your application. As the candidate, you should describe the many possible approaches and how to employ them. False or undef values are not rendered in JSX. This behavior enables us to render your component's components utilizing conditional short-circuiting and the && notation.
A practical abstraction of browser events is offered by SyntheticEvent. This abstraction simplifies how our React application interacts with browser events. This query may be used by an interviewer to gauge a candidate's familiarity with events and how React handles them. A cross-browser wrapper for the native event of the browser is SyntheticEvent. It contains the same API as the native version of the browser, which includes techniques like preventDefault and stopPropagation() (). However, SyntheticEvent functions uniformly in every browser, unlike the native events of the browser.
To conditionally display portions of your component, React allows you to incorporate conditionals like && and ternary operators. ClassNames can be thought of in the same way.
Accessing DOM nodes or React components produced by the render method is made possible through refs. The normal React dataflow of sending props down a components tree is circumvented using references. They are employed to change the child component which may include DOM elements and React components without adding new props.
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The four steps that a React Component goes through are as follows:
In our React components, states are values that we can read and update. Props are read-only values that are provided to React components. Props are comparable to function arguments that exist from outside our components, whereas states are values that exist and are specified inside our components but change over time. Within these changes to either cause the elements in which they are present to re-render, state and properties are comparable in this regard.
React has a unique feature called react fragments that let you write group child parts or components without actually generating a node in the DOM. The React.Fragment tag or an empty collection of tags are what the fragmentary syntax looks like. To put it another way, we occasionally need to group several React elements underneath a single parent, but we wouldn't want to use a div or another generic HTML element.
In React, a ref is a reference to a DOM element. The useRef hook makes it possible to generate references, which can then be put directly into a variable. To obtain a connection to the underlying DOM element, this variable is then handed to a specific React element. Now, the element or its properties are accessible via the ref's.current property.
A functional component can save state values using the useState hook function. It accepts an argument for the state's starting value. It gives back a 2-element array. The state's current value is the first component. A state-updating method makes up the second component.
The following are React's drawbacks:
A library like ReactDOM may sync a simulated representation of the actual DOM with the real DOM using the idea of the virtual DOM in react.
Some of the explanations for using references in React Hooks are as follows:
The thing is, you can either send a new value to the completed online or a parameter to the function to update the present state value.
Callback process Use of the second method is secure.
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The usage: To memoize an expensive proposition that we give it, we employ a memo hook. Memorization of previously computed values is referred to as "memoise."
The following is a list of requirements for using React Hooks:
To guarantee that all parameters are statically typed, static typing is a method that verifies code at compilation time. The design of hooks, which are essentially functions, makes sure that all of their attributes are inscribed. If you want to impose stronger static typing within your code, you may also leverage the React API with custom Hooks.
State hooks are generally used to refer to the states of React components and can be used to modify those states during runtime in accordance with the functioning of your web application.
In React 16.8, hooks are a brand-new feature. They provide state as well as other React capabilities without the need for class creation. You can remove stateful functionality from a component using hooks so that it can be tested separately and used again. You can reuse domain-specific logic with hooks without altering the component structure. Sharing Hooks amongst numerous components or with the public is now simple as a result.
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Accessing DOM elements is one of the important uses of the useRef() hook. Three steps are involved in this:
You can pass a blank array  as the second claim to useEffect if you only want to execute the function after the initial render.
A custom hook is a domain-specific function that makes use of existing react built-in hooks (such as useState, useCallback, etc.), allowing you to wrap the stateful functionality you wanted to collect in one location rather than having to copy and paste it into several components.
One of the default React hooks is useState. The function useState(0) produces a tuple with the first argument count representing the counter's current state and setCounter the method we can use to change the counter's state. The idea behind hooks is to help us keep our code more consistent and avoid class-based components if not desired or necessary. We could use the setCounter technique to update the state of the count anywhere; in this case, we are using it within the setCount function where we can do more.
No. When you use a customized Hook, all states and effects within it are completely isolated, but they provide a way to reuse stateful functionality such as creating a subscription and storing the current value.
Error boundary hooks are implemented by a few third-party packages on npm.
ComponentDidUpdate,ComponentDidMount,ComponentWillUnmount, and other existing lifecycle methods cannot be used in hooks. They are only applicable to class components. Additionally, Hooks are limited to usage in functional components exclusively.
Performance optimization is the useMemo hook's main goal.
With useMemo, you accomplish:
The following are some of React's benefits:
The Top React Hooks Interview have been covered in depth in this article. After a brief introduction, we talked about some crucial Top React Hooks Interview Questions that are frequently asked during interviews. We hope that this article will help you come up with the Top React Hooks Interview Questions.
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