在ES6中定义后导出类

Question

// test.js
class Test

export Test

---

// index.js
import {Test} from './test'

This results in a syntax error with Unexpected token . What is the correct way to export a predefined class?

---

EDIT: It is required that the class definition is separate from the export.

Answer 1

To elaborate

export {A, B};

Is the same as

// old style
exports.A = A;
exports.B = B;

Which require an import like

import {A,B} from "./somefile";

Which is the same as

// old style
var A = require("./somefile").A;
var B = require("./somefile").B;

---

However, you also could've also used export default

class Test {
  constructor() {
    console.log("it's works");
  }
}

export default Test;

Which is the same as

// old style
exports["default"] = Test;
module.exports = exports["default"];

Then import it like

import Test from "./test";
new Test();
// "it works!";

Which is the same as

// old style
var Test = require("./test");
new Test();
// "it works!";

Answer 2

正确的方法是使用export {Test} 。

Answer 3

You just need to change your test.js:

export class Test

Then

import {Test} from './test'

Answer 4

You can both do

class MyClass { }

export { MyClass }

or

export default MyClass // no semicolon

And then

import { MyClass as Stuff } from './modulepath';

or (if you declare export default)

import { default as MyClass } from './modulepath';

or simply

import MyClass from './modulepath';