Using Immutable.js, to check if a specific structure is an immutable data structure, you would use the function ________.
- checkImmutable()
- isImmutable()
- isNotMutable()
- verifyImmutable()
In Immutable.js, to check if a specific structure is an immutable data structure, you would use the isImmutable() function. This function returns true if the object is immutable and false if it's not. It's a handy utility to ensure data integrity and immutability within your application when working with Immutable.js.
Class components have built-in methods like componentWillMount, while functional components utilize ________ to achieve similar lifecycle behavior.
- useComponentWillMount
- useEffect
- useLifecycle
- useState
Class components have built-in lifecycle methods like componentWillMount, but functional components utilize the useEffect hook to achieve similar lifecycle behavior. The useEffect hook allows you to perform actions when the component mounts, updates, or unmounts, making it versatile for managing various lifecycle aspects in functional components.
How can you pass state data to the route in React Router while navigating?
- By adding the state as a query parameter in the route's URL.
- By using the this.props.state attribute in the route component.
- By using the location object and the state property when calling this.props.history.push().
- By setting the state in a global Redux store.
In React Router, you can pass state data to a route while navigating by using the location object and the state property when calling this.props.history.push(). This allows you to pass data without exposing it in the URL, which is a common approach for passing sensitive or large amounts of data between routes. The other options are not the recommended way to pass state data to a route in React Router.
If you want to share logic between two JavaScript functions, you'd create a ________.
- Closure
- Function
- Module
- Prototype
To share logic between two JavaScript functions, you'd create a "Closure." A closure is a function that has access to variables from its containing (enclosing) function's scope, allowing you to encapsulate and share logic between functions without exposing it to the global scope.
When using React.lazy(), which of the following is a required companion component to handle potential loading states or errors?
- ErrorBoundary
- LazyComponent
- LoaderComponent
- Suspense
When using React.lazy(), an ErrorBoundary component is a required companion component to handle potential loading states or errors. It acts as a fallback component in case the lazily loaded component fails to load. Suspense is used to wrap the lazy-loaded component, and the LoaderComponent is not a standard requirement.
The classNames prop in React Transition Group often requires a prefix that matches the ________ used in your CSS.
- CSS class names
- HTML tags
- JavaScript variables
- React components
In React Transition Group, the classNames prop is used to specify the CSS class names that trigger animations. These class names should match the class names used in your CSS stylesheets to ensure that the animations are applied correctly. It's essential to have consistency between the class names in your JavaScript code and your CSS.
Which pattern in React is closely related to the concept of Render Props and is often used as an alternative?
- Higher Order Components (HOCs)
- JSX Spread Operator
- Prop Drilling
- Redux
Higher Order Components (HOCs) in React are closely related to the concept of Render Props and are often used as an alternative. Both patterns enable component composition and sharing of logic, but they do so in different ways. While Render Props pass a function as a prop, HOCs wrap components to provide additional functionality. This makes HOCs a viable alternative when Render Props may not be the best fit for a particular scenario.
Which library provides easy-to-use animations specifically designed for React?
- React Native Animations
- React Spring
- React Motion
- React Magic
React Spring is a popular library specifically designed for animations in React. It provides a simple and declarative way to create animations, making it a preferred choice for developers looking to add animations to their React applications. The other options are either unrelated to React animations or not commonly used for this purpose.
Which React feature allows you to display a fallback UI while a component tree waits for a component to be lazily loaded?
- Context
- Props
- State
- Suspense
React's Suspense feature allows you to display a fallback UI while a component tree waits for a component to be lazily loaded. Suspense helps manage the loading state of components and provides a smooth user experience during asynchronous component loading. While State, Props, and Context are essential in React, Suspense is specifically designed for handling loading states.
How does a Portal maintain the parent-child relationship in terms of events, even if it renders children outside the parent DOM hierarchy?
- Portals automatically attach the portal content to the parent component's DOM hierarchy.
- Portals rely on the browser's native event handling mechanisms to maintain event relationships.
- Portals use a custom event system to simulate the parent-child event relationship.
- Portals use event bubbling and capture phases to propagate events from the portal content to its parent component, preserving the relationship.
Portals maintain parent-child event relationships by leveraging event propagation through event bubbling and capture phases. When an event occurs within the portal content, it bubbles up to the parent component, allowing you to handle events seamlessly as if the content were still within the parent DOM hierarchy. Portals don't use a custom event system, automatic attachment to the parent DOM, or browser-native mechanisms to achieve this.
Which of the following is a higher order component that memoizes the rendered output of the passed component preventing unnecessary renders?
- memo
- useCallback
- useMemo
- useState
The higher order component in React that memoizes the rendered output of the passed component, preventing unnecessary renders, is memo. It's often used for functional components to optimize rendering performance by re-rendering only when the props change. useMemo and useCallback are hooks used for different purposes, and useState is used to manage component state.
The event that service workers primarily listen to, in order to intercept and handle network requests, is called ________.
- Fetch Event
- Intercept Event
- Network Event
- Service Event
Service workers primarily listen to the "Fetch Event" to intercept and handle network requests. When a web application makes network requests, service workers can intercept and customize the responses, enabling various functionalities like caching, offline support, and more. Understanding the "Fetch Event" is fundamental to working with service workers in web development.