javascript - JavaScript 导出语法之间有什么区别？

Question

我试图了解在 javascript 中导出组件的方法之间是否存在任何差异。我了解默认导出的工作原理以及如何导出变量，例如:

// when exporting a function:
export function foo () {}
// you can import it as
import {foo} from "foo";

// default export
export default class foo {}
//then:
import foo from "foo";

但我见过这样的案例:

export {foo as default} from "foo";
export {foo as default, bar} from "foo";
export {default} from "foo";
export {default as foo} from "foo";

有人可以解释一下 default 关键字在上述 4 种情况中的含义以及如何导入它吗？

Answer 1

// import foo and export it as default
export {foo as default} from "foo"; 

// import foo and export it as default
// import bar and immediately export bar
export {foo as default, bar} from "foo";

// import default as foo and export it
export {default as foo} from "foo"; 

// re-exporting the default export 
export {default} from "foo";

所有这些都是再导出，意思是进口东西然后立即导出。