What is a common naming convention for HOCs in the React community?
- Starting with "ReactHOC_"
- Using PascalCase for component names.
- Prefixing with "with" followed by the component name.
- Starting with "hoc_"
In the React community, a common naming convention for Higher Order Components (HOCs) is to prefix them with "with" followed by the component name they enhance. This convention helps developers identify HOCs and understand their purpose in enhancing components. The other naming conventions mentioned in options 1, 2, and 4 are not as commonly used in the React community for HOCs.
You're optimizing a React application and notice that a particular component re-renders frequently, even though its props and state seem unchanged. Which tool or method can help you verify and prevent this behavior?
- Applying shouldComponentUpdate lifecycle method to the component.
- Enabling PureComponent for the component.
- Profiling with React DevTools.
- Using React.memo for the component.
In this scenario, you can utilize React.memo to optimize the component's re-renders. React.memo is a higher-order component (HOC) that memoizes a component, preventing it from re-rendering when its props remain unchanged. React DevTools can help you identify the problem, but React.memo is the method to prevent unnecessary re-renders.
The TypeScript keyword used to create a type that can be one of several types is called ________.
- union
- any
- object
- function
The TypeScript keyword used to create a type that can be one of several types is called union. Unions are used to specify that a value can have one of several possible types. This is valuable for scenarios where a variable or property can accept multiple data types. The other options (any, object, function) do not specifically define a type that can be one of several types.
You're refactoring a higher-order component that injects props into wrapped components. You notice that the component tree is getting deeper and more complex. Which pattern can help flatten the component tree while still sharing the logic?
- Adapter Pattern
- Composite Pattern
- Facade Pattern
- Proxy Pattern
The Proxy Pattern can help flatten the component tree while still sharing the logic. It allows you to control access to an object by creating a surrogate or placeholder for it. In the context of React or similar frameworks, a proxy component can be used to encapsulate complex logic, making the component tree shallower and more maintainable. The other patterns listed do not directly address this issue.
You are building a MobX store for a to-do application. Whenever a task is marked as completed, you want to automatically update the total count of completed tasks. Which MobX feature would be best suited for this?
- Actions
- Computed Property
- Observables
- Reactions
In this scenario, a Computed Property in MobX would be best suited. Computed properties automatically update whenever the observable data they depend on changes. By defining a computed property for the total count of completed tasks, you ensure it updates automatically when the completion status of tasks changes. It's an efficient way to derive data from observables.
In Redux, to handle asynchronous logic, you often use middleware like ________.
- Redux-logger
- Redux-router
- Redux-saga
- Redux-thunk
In Redux, handling asynchronous logic is typically done using middleware like Redux-thunk. Redux-thunk allows you to write action creators that return functions instead of plain objects, enabling asynchronous operations like API calls within Redux. Redux-saga, Redux-logger, and Redux-router serve different purposes and are not used for handling asynchronous logic.
In scenarios where performance is critical, how can immutability assist in optimizing React's reconciliation process?
- It adds complexity to the reconciliation process.
- It increases the frequency of deep component rendering.
- It prevents React from performing reconciliation.
- It reduces the need for shallow comparisons during updates.
Immutability can optimize React's reconciliation process by reducing the need for shallow comparisons during updates. Since immutable data structures don't change, React can quickly determine if props or state have changed by comparing references, resulting in faster updates and improved performance, especially in large and complex React applications.
HOCs can introduce potential naming collisions due to the automatic passing of ________.
- Context
- Methods
- Props
- State
Higher-Order Components (HOCs) automatically pass props to the wrapped component. This can introduce potential naming collisions if the same prop name is used within the HOC and the wrapped component. Developers need to be aware of this and avoid naming conflicts when creating or using HOCs.
Redux enhances its capabilities and handles asynchronous operations using middlewares like redux-thunk and ________.
- redux-logger
- redux-middleware
- redux-promise
- redux-saga
Redux utilizes middlewares like redux-thunk or redux-saga to handle asynchronous operations. In this context, redux-saga is a popular choice for handling complex asynchronous flows. While other middlewares like redux-promise and redux-logger are used in Redux, they don't primarily focus on handling asynchronous operations like redux-saga or redux-thunk.
How does React's diffing algorithm handle the update of lists?
- By comparing the old list to the new list element by element.
- By delegating list updates to the browser's rendering engine.
- By replacing the old list with the new list entirely.
- By using a hashing function to identify changes.
React's diffing algorithm updates lists by comparing the old list to the new list element by element. It identifies changes, additions, and removals, allowing for efficient updates without recreating the entire list. This approach is known as "keyed reconciliation" and helps minimize the DOM manipulation required. This is a crucial concept in optimizing React applications.