此实验性语法需要启用以下解析器插件之一：'classPrivateProperties, classPrivateMethods'答案

【问题标题】：This experimental syntax requires enabling one of the following parser plugin(s): 'classPrivateProperties, classPrivateMethods'此实验性语法需要启用以下解析器插件之一：'classPrivateProperties, classPrivateMethods'
【发布时间】：2021-06-01 00:16:48
【问题描述】：

我正在尝试使用 parcel 捆绑我的 javascript 文件，一切正常，除了我在运行 npm run start 时遇到此问题

@parcel/transformer-js: This experimental syntax requires enabling one of the following parser plugin(s): 'classPrivateProperties, classPrivateMethods'

经过一番谷歌搜索后，我发现我需要安装 classPrivateProperties 和 classPrivateMethods，所以我安装了，但这里出现的同样问题是我的 package.json 文件

{
  "name": "starter",
  "version": "1.0.0",
  "description": "",
  "main": "index.html",
  "scripts": {
    "start": "parcel index.html",
    "build": "parcel build index.html"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "@babel/plugin-proposal-private-methods": "^7.13.0",
    "@babel/plugin-proposal-private-property-in-object": "^7.13.0",
    "@parcel/optimizer-cssnano": "^2.0.0-nightly.612",
    "@parcel/optimizer-htmlnano": "^2.0.0-nightly.612",
    "@parcel/packager-css": "^2.0.0-nightly.612",
    "@parcel/packager-html": "^2.0.0-nightly.612",
    "@parcel/transformer-css": "^2.0.0-nightly.612",
    "@parcel/transformer-html": "^2.0.0-nightly.612",
    "@parcel/transformer-postcss": "^2.0.0-nightly.612",
    "@parcel/transformer-posthtml": "^2.0.0-nightly.612",
    "@parcel/transformer-sass": "^2.0.0-nightly.612",
    "node": "^15.10.0",
    "parcel": "^2.0.0-beta.1",
    "postcss": "^8.2.6",
    "sass": "^1.26.10"
  },
  "dependencies": {
    "core-js": "^3.6.5",
    "fractional": "^1.0.0",
    "regenerator-runtime": "^0.13.7"
  },
  "plugins": [
    "@babel/plugin-proposal-private-methods",
    "@babel/plugin-proposal-private-property-in-object"
  ]
}

感谢您的帮助

【问题讨论】：

标签： javascript babeljs package.json parcel

【解决方案1】：

如果你在谈论 Parcel.js，你需要安装和配置一些 Babel 插件，以启用类私有属性和方法：

用 NPM 安装这个包：

npm i @babel/plugin-proposal-private-methods @babel/plugin-proposal-class-properties
在项目的根文件夹中创建.babelrc 文件：

    {
      "plugins": [
        "@babel/plugin-proposal-class-properties",
        "@babel/plugin-proposal-private-methods"
      ]
    }

再次运行 Parcel。

【讨论】：

【解决方案2】：

我通过安装插件并将 .babelrc 配置文件添加到项目的根目录解决了这个问题。

{
  "plugins": [
    "@babel/plugin-proposal-class-properties",
    "@babel/plugin-proposal-private-methods"
  ]
}

【讨论】：