javascript - 无法使用 Node 运行 babel 转译文件

Question

这是我刚刚修改为使用 es6 import 以测试 app.js 的转译过程的非常基本的 express 样板代码:

import "babel-polyfill";
import * as express from "express"
var app = express();


app.get('/', function (req, res) {
  res.send('Hello World!');
});

app.listen(3000, function () {
  console.log('Examdple app listening on port 3000!');
});

在 .babelrc 中

{
    "presets": [
     "es2015"
    ],
    "plugins": ["transform-runtime",
      "transform-es2015-classes"]
  }

生成的转译代码 app-compiled.js:

"use strict";

require("babel-polyfill");

var _express = require("express");

var express = _interopRequireWildcard(_express);

function _interopRequireWildcard(obj) { if (obj && obj.__esModule) { return obj; } else { var newObj = {}; if (obj != null) { for (var key in obj) { if (Object.prototype.hasOwnProperty.call(obj, key)) newObj[key] = obj[key]; } } newObj.default = obj; return newObj; } }

var app = express();

app.get('/', function (req, res) {
  res.send('Hello World!');
});

app.listen(3000, function () {
  console.log('Examdple app listening on port 3000!');
});

//# sourceMappingURL=app-compiled.js.map

现在尝试运行/usr/local/bin/node app-compiled.js :

var app = express();
          ^
TypeError: express is not a function

或/usr/local/bin/node app.js

/Users/Documents/Apps_And_Sites/Js_Apps/projectname/app.js:1
(function (exports, require, module, __filename, __dirname) { import "babel-polyfill";
                                                              ^^^^^^

SyntaxError: Unexpected reserved word

此外，当我不使用 polyfill 时，它会出现相同的“导入”错误，但没有封装函数。

如果这有帮助，package.json 中的依赖项:

 "devDependencies": {
    "babel-cli": "^6.9.0",
    "babel-core": "^6.9.1",
    "babel-eslint": "^6.0.4",
    "babel-plugin-syntax-flow": "^6.8.0",
    "babel-plugin-transform-class-properties": "^6.9.1",
    "babel-plugin-transform-flow-strip-types": "^6.8.0",
    "babel-plugin-transform-runtime": "^6.9.0",
    "babel-polyfill": "^6.9.1",
    "babel-preset-es2015": "^6.9.0",
    "eslint-plugin-flowtype": "^2.2.7",
    "flow-bin": "^0.26.0"
  },
  "dependencies": {
    "babel-runtime": "^6.9.2",
    "express": "^4.13.4"
  }
}

在我的 webstorm ide 中，我使用这些参数设置了 babel:

Program: node_modules/babel-cli/bin/babel.js

Arguments: --source-maps --out-file $FileNameWithoutExtension$-compiled.js $FilePath$

Output paths to refresh: $FileNameWithoutExtension$-compiled.js:$FileNameWithoutExtension$-compiled.js.map

为什么 Node 不能运行 babel 转译后的代码？

Answer 1

您的 import 在语法上是正确的，但对于您的用法是错误的，它应该只是:

import express from 'express';