How would you provide multiple contexts to a single component?
- You can achieve this only with Redux.
- You can nest multiple
components. - You can use a higher-order component (HOC) for this purpose.
- You can't provide multiple contexts to a single component.
To provide multiple contexts to a single component in React, you can nest multiple components within your component's structure. Each provider will manage its own context, allowing you to access and update multiple pieces of state within a single component.
When testing React components, ________ is a utility provided by the React Testing Library to render components.
- renderComponent
- testComponent
- createComponent
- mountComponent
When testing React components, the React Testing Library provides the renderComponent utility to render components for testing. This utility allows you to simulate component rendering and interactions in a testing environment. The other options are not standard utilities provided by the React Testing Library.
You're reviewing a junior developer's code and notice they're using regular HTML tags in a React component. What might be a concern?
- Compatibility issues between browsers may arise.
- It has no impact on the application as React can handle both HTML and JSX.
- It simplifies code readability and maintenance.
- This approach improves React component performance.
The use of regular HTML tags within a React component can lead to compatibility issues between browsers. React relies on its virtual DOM to efficiently update the UI, and mixing regular HTML tags can break this process. While React can handle both HTML and JSX, it's recommended to stick with JSX to ensure optimal performance and compatibility across browsers.
What is the primary role of a reducer in Redux?
- Controlling the UI components.
- Handling HTTP requests.
- Managing the application's state.
- Validating user input.
A reducer's primary role in Redux is to manage the application's state. Reducers are responsible for specifying how the application's state changes in response to actions. They take the current state and an action as input and return a new state. While other components like middleware may handle HTTP requests or UI components control the user interface, reducers are specifically designed for state management.
The Redux principle that states all state updates are centralized and occur one by one in a strict order is known as ________.
- Immutable State
- One-Way Flow
- Reducer Composition
- Single Source of Truth
The Redux principle that states all state updates are centralized and occur one by one in a strict order is known as the "Single Source of Truth." This principle ensures that there's only one place (the Redux store) where the application's state is managed, and updates are processed sequentially. It's a key concept that helps maintain predictability and reliability in Redux applications.
When you want to access the current value of a context, you would use the ________ method of the context object in class components.
- this.context()
- this.get()
- this.getContext()
- this.getCurrentContext()
When you want to access the current value of a context in class components, you would use the this.context() method of the context object. This method allows you to access the context's current value within the component where the context is consumed.
If you have a counter set to 0 and call setCounter(prev => prev + 1) three times consecutively inside an event handler, what will be the value of the counter?
- 1
- 2
- 3
- 4
The value of the counter will be 3. Each call to setCounter(prev => prev + 1) increments the counter by 1 based on the previous value. Since this is done three times consecutively, the counter goes from 0 to 1, then 1 to 2, and finally 2 to 3.
What is the key advantage of using a cache-first strategy in PWAs?
- Enhanced security.
- Faster initial page load times.
- Improved server scalability.
- Reduced client-side processing.
The key advantage of a cache-first strategy in Progressive Web Apps (PWAs) is faster initial page load times. When a PWA caches resources like HTML, CSS, and JavaScript on the client side, it can load the core content quickly from the cache, providing a smoother and more responsive user experience. This is crucial for PWAs to provide near-native app performance.
You have a button inside a card component. When the button is clicked, an action is triggered, but when the card is clicked, a modal appears. However, clicking the button also triggers the modal. How can you prevent this?
- Use the event.stopPropagation() method on the button click event.
- Use a higher-order component to wrap the card component.
- Remove the button from the card component.
- Add more event listeners to the modal.
To prevent the card click event from propagating to the modal when the button inside the card is clicked, you should use event.stopPropagation() on the button's click event. This prevents the click event from bubbling up to the card and triggering the modal. The other options are not suitable for addressing this specific issue.
For performance reasons, when using styled-components, it's advisable to avoid using the ______ prop too frequently.
- :style
- :performance
- :should-update
- :attrs
In styled-components, it's advisable to avoid using the ":attrs" prop too frequently for performance reasons. The ":attrs" prop allows you to pass additional attributes to a styled component, but excessive use can impact performance. It's recommended to use it judiciously when needed. The other options are not directly related to performance considerations in styled-components.