For optimal user experience, it's recommended to use Suspense and React.lazy() for components that are at least ________ in size.
- Large
- Medium
- Small
- Varying sizes
For optimal user experience, it's recommended to use Suspense and React.lazy() for components that are at least medium in size. This is because the cost of loading and displaying a smaller component dynamically might outweigh the benefits of lazy loading. However, for very large components, lazy loading is often beneficial. The exact threshold for what constitutes "medium" can vary based on the specific application and performance considerations.
What is the primary purpose of Jest in the React ecosystem?
- Managing state in React components.
- Routing in React applications.
- Styling React components.
- Testing React components.
The primary purpose of Jest in the React ecosystem is to facilitate the testing of React components. Jest is a widely-used testing framework for JavaScript applications, and it includes features for writing unit tests, integration tests, and snapshot tests for React components. It provides a convenient and efficient way to ensure that your React code functions as expected.
In the context of Immutable.js, what is the difference between the merge and mergeDeep methods?
- There is no difference between merge and mergeDeep; they are synonyms.
- merge performs a shallow merge, while mergeDeep performs a deep merge.
- mergeDeep performs a shallow merge, while merge performs a deep merge.
- mergeDeep performs a shallow merge, while mergeDeep performs a deep merge.
In Immutable.js, merge and mergeDeep are distinct methods. merge performs a shallow merge, meaning it merges top-level properties, while mergeDeep performs a deep merge, merging nested properties recursively. Understanding this difference is crucial for handling complex data structures and preventing unintended data overwrites or loss.
In the context of GraphQL, what does Apollo Client help with?
- Querying and managing data from a GraphQL server.
- Running unit tests in React.
- State management in React applications.
- Styling React components.
Apollo Client is primarily used in the context of GraphQL to query and manage data from a GraphQL server. It simplifies data fetching, caching, and state management for GraphQL queries and mutations in React applications. It is not related to styling or unit testing React components, which are different concerns.
What is the primary purpose of using GraphQL with React?
- To create responsive, mobile-friendly designs.
- To efficiently fetch and manage data from a server.
- To manage state in React components.
- To style React components.
The primary purpose of using GraphQL with React is to efficiently fetch and manage data from a server. GraphQL allows you to request only the data you need, reducing over-fetching and under-fetching of data, which can be common in RESTful APIs. While React manages state and rendering, GraphQL focuses on data retrieval and manipulation.
When a Websocket connection is closed unexpectedly, the Websocket object emits a ________ event.
- close
- disconnect
- error
- terminate
When a WebSocket connection is closed unexpectedly, the WebSocket object emits an error event. This event is crucial for handling unexpected disconnections and potential issues in your WebSocket communication. Developers can listen for this event and implement error-handling logic as needed.
Consider a scenario where you want to share logic between multiple components without adding extra layers in the component tree. Which pattern would best fit this requirement?
- Higher-Order Component (HOC)
- Render Props
- Redux
- React Context API
In this scenario, Higher-Order Components (HOCs) are a suitable choice. HOCs allow you to share logic between multiple components without altering the component tree structure. You can wrap components with an HOC to provide them with additional functionality, making it a powerful tool for reusing logic across your React application. The other options are not primarily designed for this specific use case.
To transform an Immutable.js List into a native JavaScript array, you would use the method ________.
- convertToArray()
- listToArray()
- toArray()
- toNativeArray()
To transform an Immutable.js List into a native JavaScript array, you would use the method toArray(). This method is used to convert an Immutable.js List into a plain JavaScript array, making it easier to work with native JavaScript functions.
In React Native, instead of using HTML's , you would use ________.
In React Native, instead of using HTML's
, you would use the component. The component is a fundamental building block for creating layouts and structuring content in React Native applications. It is used to group and style elements much like
in HTML. , , and are not standard React Native components.
In MobX, which decorator is used to mark a property as observable?
- @component
- @observable
- @state
- @watch
In MobX, the @observable decorator is used to mark a property as observable. When a property is marked as observable, MobX can track changes to it and automatically update any components that depend on it when it changes. This is a key feature for reactive state management in MobX.
In React Native, instead of using HTML's
, you would use the component. The component is a fundamental building block for creating layouts and structuring content in React Native applications. It is used to group and style elements much like
in HTML. , , and are not standard React Native components.
In MobX, which decorator is used to mark a property as observable?
- @component
- @observable
- @state
- @watch
In MobX, the @observable decorator is used to mark a property as observable. When a property is marked as observable, MobX can track changes to it and automatically update any components that depend on it when it changes. This is a key feature for reactive state management in MobX.