1.vscode编辑器运行项目成功后有警告⚠ 如下：

One of your dependencies, babel-preset-react-app, is importing the
"@babel/plugin-proposal-private-property-in-object" package without
declaring it in its dependencies. This is currently working because
"@babel/plugin-proposal-private-property-in-object" is already in your
node_modules folder for unrelated reasons, but it may break at any time.

babel-preset-react-app is part of the create-react-app project, which
is not maintianed anymore. It is thus unlikely that this bug will
ever be fixed. Add "@babel/plugin-proposal-private-property-in-object" to
your devDependencies to work around this error. This will make this message
go away.

 如图：

 原因：

这个错误是由于create-react-app项目已经不再维护，所以babel-preset-react-app依赖的 "@babel/plugin-proposal-private-property-in-object"包可能不再更新，导致出现未声明依赖的错误。

要解决这个问题，你可以在你的package.json文件中添加"@babel/plugin-proposal-private-property-in-object"包到devDependencies中。这样，当你运行项目时，错误信息应该会消失

解决方法：

执行如下命令即可

npm install --save-dev @babel/plugin-proposal-private-property-in-object