`export default xxx`和`export default xxx = fn`有什么区别？

Question

我在项目中使用babel + webpack +做出反应。它适用于Chrome，但它只能以第一种方式运行：

request.js

const fetch = (options) => {
    return new Promise((resolve, reject) => {
    ...
    $.ajax(options);
 })
}

export default fetch;

如果我使用export default fetch = fn，我会收到错误。

.babelrc

{
  "presets": [["es2015", { "modules": false }], "stage-2", "react"],
  "plugins": [
    "transform-object-assign",
    // "transform-strict-mode"
    // ["transform-runtime", {"helpers": false,"polyfill": false,"regenerator": true}],
    "transform-node-env-inline",
    //"transform-remove-strict-mode",
    //"transform-strict-mode",
    ["react-transform", {
      "transforms": [{
        "transform": "react-transform-hmr",
        "imports": ["react"],
        "locals": ["module"]
      }, {
        "transform": "react-transform-catch-errors",
        "imports": ["react", "redbox-react"]
      }]
    }]
  ],

  "env": {
    "development": {
       "plugins": ["react-hot-loader/babel"]
    }
  }
}

那么，为什么？感谢。

Answer 1

因为这不是有效的JS语法。

试试这个：

export default function fetch() {
  ...
}