Question

我有以下代码...

// index.mjs

class DoSomething{
    constructor(){
        console.log("Constructing");
    }
    doSomethingElse(){
        console.log("Something else");
    }
}

export { DoSomething }

它使用以下webpack规则进行编译...

  rules: [
      {
          test: /\.mjs$/,
          exclude: /(node_modules|bower_components)/,
          use: {
              loader: 'babel-loader',
              options: {
                  presets: ['@babel/preset-env']
              }
          }
      }
  ]

这会产生...

 //dist/sce.cjs
...
var DoSomething =
/*#__PURE__*/
function () {
  function DoSomething() {
    _classCallCheck(this, DoSomething);
    console.log("Constructing");
  }

  _createClass(DoSomething, [{
    key: "doSomethingElse",
    value: function doSomethingElse() {
      console.log("Something else");
    }
  }]);
  return DoSomething;
}();

但是当我尝试在这样的CJS脚本中实例化它时...

var lib = require("../dist/sce.cjs");
(function(){
    var instance = new lib.DoSomething();
    instance.doSomethingelse();
})()

我明白了

TypeError：lib.DoSomething不是构造函数

我应该如何导入呢？

Answer 1

这有效...

const path = require('path');
module.exports = {
  entry: path.resolve(__dirname, 'src/index.mjs'),
  output: {
      filename: 'sce.cjs',
      libraryTarget: 'commonjs'
  },
  module: {
      rules: [
          {
              test: /\.mjs$/,
              exclude: /(node_modules|bower_components)/,
              use: {
                  loader: 'babel-loader',
                  options: {
                      presets: ['@babel/preset-env']
                  }
              }
          }
      ]
  }
}
...
var DoSomething = require("../dist/sce.cjs").DoSomething;
(function(){
    var instance = new DoSomething();
    instance.doSomethingElse();
})()

使用babel编译到es5后，如何实例化新类？

1 个答案: