React 面接の質問と回答

質問 11. What are states in React?

States form to be one of the vital aspects of React. It is considered as a source of data or objects that control aspects such as component behavior and rendering. In React, states are used to easily create dynamic and interactive components.

質問 12. What are props in React?

Props are the shorthand name given to properties in React. Props are read-only components that are immutable in nature. In an application, props follow a hierarchy that is passed down from parents to child components. However, the reverse is not supported. This is done to ensure that there is only a single directional flow in data at all times.

質問 13. What is the use of an arrow function in React?

An arrow function is used to write an expression in React. It allows users to manually bind components easily. The functionality of arrow functions can be very useful when you are working with higher-order functions particularly.

Example: 

MyInput onChange={ (e) => this.handleOnChange(e) }

質問 14. What is a higher-order component in React?

Higher-order components (HOCs) are a widely used technique in React for applying concepts that involve the component reusability logic. They are not a native part of the React API and allow users to easily reuse the code and bootstrap abstraction.

HOCs are also used to allow simple sharing of behaviors across all of the components in React, adding more advances to the efficiency and functioning of the application.

質問 15. What is the meaning of create-react-app in React?

The create-react app in React is a simple command-line interface (CLI) that is used in the creation of React applications, which have no build configuration.

All tools are pre-configured when using the CLI, and this allows users to focus on the code more than on dependencies to develop the application.

The following syntax is used to start a simple project in React:

Create-react-app my-app