es6转es5_es6转es5插件

npm init -y

npm install @babel/cli @babel/core @babel/preset-env babel-plugin-transform-es2015-modules-umd -D

{
  "presets": [
    "@babel/preset-env"
  ],
  "plugins": ["transform-es2015-modules-umd"]
}

"scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "babel": "babel es6.js -o es5.js"
  },

npm run babel

export class A {
  a = 0
  constructor(v = 1) {
    this.a = v
  }
  getA() {
    return this.a
  }
  setA(v) {
    this.a = v
  }
}

const a = new A()
a.setA(10)
console.log(a);

"use strict";

(function (global, factory) {
  if (typeof define === "function" && define.amd) {
    define(["exports"], factory);
  } else if (typeof exports !== "undefined") {
    factory(exports);
  } else {
    var mod = {
      exports: {}
    };
    factory(mod.exports);
    global.undefined = mod.exports;
  }
})(void 0, function (exports) {
  "use strict";

  Object.defineProperty(exports, "__esModule", {
    value: true
  });

  function _classCallCheck(instance, Constructor) {
    if (!(instance instanceof Constructor)) {
      throw new TypeError("Cannot call a class as a function");
    }
  }

  function _defineProperties(target, props) {
    for (var i = 0; i < props.length; i++) {
      var descriptor = props[i];
      descriptor.enumerable = descriptor.enumerable || false;
      descriptor.configurable = true;
      if ("value" in descriptor) descriptor.writable = true;
      Object.defineProperty(target, descriptor.key, descriptor);
    }
  }

  function _createClass(Constructor, protoProps, staticProps) {
    if (protoProps) _defineProperties(Constructor.prototype, protoProps);
    if (staticProps) _defineProperties(Constructor, staticProps);
    return Constructor;
  }

  function _defineProperty(obj, key, value) {
    if (key in obj) {
      Object.defineProperty(obj, key, {
        value: value,
        enumerable: true,
        configurable: true,
        writable: true
      });
    } else {
      obj[key] = value;
    }

    return obj;
  }

  var A = exports.A = function () {
    function A() {
      var v = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : 1;

      _classCallCheck(this, A);

      _defineProperty(this, "a", 0);

      this.a = v;
    }

    _createClass(A, [{
      key: "getA",
      value: function getA() {
        return this.a;
      }
    }, {
      key: "setA",
      value: function setA(v) {
        this.a = v;
      }
    }]);

    return A;
  }();

  var a = new A();
  a.setA(10);
  console.log(a);
});