试图理解:从"React"导入React，{component}； [英] trying to understand: import React, {component} from 'React';

问题描述

我正在研究如何使React.js与后端一起工作.我已经看到了这种语法:

I am working on how to have React.js work with a backend. I have seen this syntax:

从'React'导入React，{component};

import React, {component} from 'React';

为什么在这里列出了{component}?在我看来，您当然希望使用组件.所以我不知道为什么{component}在那里.

Why is {component} listed there? In my mind, you would of course want to use components. So I don't know why {component} is there.

我认为从"React"导入React就足够了……意思是把所有的React都给我".但是显然我在这里缺少某种概念.

I would think import React from 'React' would be enough... meaning "give me all of React". But obviously I am missing some sort of concept here.

谢谢.

推荐答案

React 是 react 包的默认导出，而 Component 是该程序包中的命名导出.你可以做

React is the default export from the react package, whereas Component is a named export in that package. You can either do

import React from 'react';

class MyClass extends React.Component { ... }

或

import React, { Component } from 'react';

class MyClass extends Component { ... }

在此处中了解有关JavaScript导出的更多信息.>

Read more about JavaScript exports here

编辑:实际上，React使用一种不同的模式，称为在默认导出中公开API，它具有与命名导出相同的导入约定-您可以查看其源

Actually, React uses a different pattern called exposing an API on the default export, which has the same import convention as named exports - you can look at their source here

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