为什么我不能在ES6中导出导出声明的函数? [英] why I can't export export a declared function in ES6?

问题描述

我已经阅读了MDN的文档，好吧，主要是关于新模块功能的好处，让我感到困惑的是有关 export 的小东西，现在，让我们来看一下:

I have read docs from MDN, ok, mainly it's good about the new module feature, what makes me confused is the small things about export, now, let's see:

当我

export function foo(x) {
   return x * x;
}

或

export const foo = (x) => {
  return x * x
}

都可行；

但如果

const foo = (x) => {
  return x * x
}
export foo  // failed

我知道这里应该是 export {foo} ，但是，为什么呢?有什么区别，应该可以.很高兴听到一些精灵的想法.

I know here should be export {foo}, but, why? what's the difference, that should be work. glad to hear some genies ideas.

推荐答案

ES模块仅支持几种语法变体以便进行静态分析.

ES modules support only several syntax variations in order to be statically analyzed.

根据参考，变体为:

export { name1, name2, …, nameN };
export { variable1 as name1, variable2 as name2, …, nameN };
export let name1, name2, …, nameN; // also var, function
export let name1 = …, name2 = …, …, nameN; // also var, const

export default expression;
export default function (…) { … } // also class, function*
export default function name1(…) { … } // also class, function*
export { name1 as default, … };

export * from …;
export { name1, name2, …, nameN } from …;
export { import1 as name1, import2 as name2, …, nameN } from …;

export foo 不在其中.不支持，无法使用.

export foo is not among them. It is not supported and cannot be used.

这篇关于为什么我不能在ES6中导出导出声明的函数?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！