The MobX ________ function ensures that a function is derived from the current state but doesn't cause side effects.
- action
- computed
- mutation
- observable
The MobX computed function ensures that a function is derived from the current state but doesn't cause side effects. Computed properties are derived values in MobX that are automatically kept in sync with the state they depend on. They are read-only and automatically update when their dependencies change. This is crucial for ensuring predictable and efficient reactivity in MobX.
What is the primary mechanism to pass data from a parent to a child component in React?
- Context API
- Props
- Redux
- State
The primary mechanism to pass data from a parent to a child component in React is through props (short for properties). Props allow you to pass data from a parent component to a child component as read-only properties. While React provides other mechanisms like state, Redux, and Context API for managing and sharing data, props is the most direct and common method for parent-child communication.
When using dynamic imports in Webpack, the import() function returns a promise that resolves into a(n) ________.
- Array
- Module
- Object
- String
When using dynamic imports in Webpack, the import() function returns a promise that resolves into a module. This module can then be used to access the exports of the dynamically imported code. Webpack treats dynamic imports as separate chunks that are loaded on-demand, enhancing performance by reducing initial bundle size. Understanding this is crucial for handling dynamically loaded code correctly.
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.
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.
What potential issues might arise if event handlers are not properly bound in class components?
- Components may fail to render.
- Event handlers may execute too slowly.
- Event handlers will have higher priority.
- Memory leaks may occur.
If event handlers are not properly bound in class components, memory leaks can occur. This happens because the event handlers may retain references to component instances, preventing them from being garbage collected. It can lead to performance issues and potential memory exhaustion. Correctly binding event handlers is essential for avoiding these issues.
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.
What potential issues might arise if event handlers are not properly bound in class components?
- Components may fail to render.
- Event handlers may execute too slowly.
- Event handlers will have higher priority.
- Memory leaks may occur.
If event handlers are not properly bound in class components, memory leaks can occur. This happens because the event handlers may retain references to component instances, preventing them from being garbage collected. It can lead to performance issues and potential memory exhaustion. Correctly binding event handlers is essential for avoiding these issues.