我不明白是怎么回事。 节点v5.6.0 NPM v3.10.6

代码:

function (exports, require, module, __filename, __dirname) {
    import express from 'express'
};

错误:

SyntaxError: Unexpected token import
    at exports.runInThisContext (vm.js:53:16)
    at Module._compile (module.js:387:25)
    at Object.Module._extensions..js (module.js:422:10)
    at Module.load (module.js:357:32)
    at Function.Module._load (module.js:314:12)
    at Function.Module.runMain (module.js:447:10)
    at startup (node.js:140:18)
    at node.js:1001:3

当前回答

如果你仍然不能使用“import”,下面是我处理它的方法: 只需将其转换为节点友好的要求。例子:

import { parse } from 'node-html-parser';

等于:

const parse = require('node-html-parser').parse;

其他回答

如果你可以使用'babel',试着在package.json(——presets=es2015)中添加构建脚本,如下所示。它可以预编译导入代码到es2015

"build": "babel server --out-dir build --presets=es2015 && webpack"

在我的情况下,它是看着.babelrc文件,它应该包含这样的东西:

{
  "presets": ["es2015-node5", "stage-3"],
  "plugins": []
}

巴别塔7号提案 您可以添加开发依赖项吗

npm i -D @babel/core @babel/preset-env @babel/register

并在根目录中添加。babelrc

{
"presets": [
  [
    "@babel/preset-env",
    {
      "targets": {
        "node": "current"
     }
    }
  ]
 ]
}

并添加到.js文件中

require("@babel/register")

或者如果你在cli中运行它,你可以使用require钩子作为-r @babel/register, ex。

$node -r @babel/register executeMyFileWithESModules.js

不幸的是,Node.js还不支持ES6的导入。

要完成您要做的事情(导入Express模块),这段代码应该足够了

var express = require("express");

另外,确保通过运行安装了Express

$ npm install express

有关学习Node.js的更多信息,请参阅Node.js文档。

作为Node.js v12(这可能是相当稳定的现在,但仍然标记为“实验”),你有两个选项使用ESM (ECMAScript模块)在Node.js(文件,有第三种方法计算字符串),以下是文档所说的:

The --experimental-modules flag can be used to enable support for ECMAScript modules (ES modules). Once enabled, Node.js will treat the following as ES modules when passed to node as the initial input, or when referenced by import statements within ES module code: Files ending in .mjs. Files ending in .js, or extensionless files, when the nearest parent package.json file contains a top-level field "type" with a value of "module". Strings passed in as an argument to --eval or --print, or piped to node via STDIN, with the flag --input-type=module. Node.js will treat as CommonJS all other forms of input, such as .js files where the nearest parent package.json file contains no top-level "type" field, or string input without the flag --input-type. This behavior is to preserve backward compatibility. However, now that Node.js supports both CommonJS and ES modules, it is best to be explicit whenever possible. Node.js will treat the following as CommonJS when passed to node as the initial input, or when referenced by import statements within ES module code: Files ending in .cjs. Files ending in .js, or extensionless files, when the nearest parent package.json file contains a top-level field "type" with a value of "commonjs". Strings passed in as an argument to --eval or --print, or piped to node via STDIN, with the flag --input-type=commonjs.