启动 webpack-dev-server 时配置对象无效

Question

我刚刚在我的 Rails 5.2 应用程序上安装了 webpacker，在尝试运行 bin/webpack-dev-server 时出现以下错误：

 ✖ ｢wds｣: Invalid configuration object. Webpack has been initialised using a configuration object that does not match the API schema.
 - configuration.entry should be one of these:
   function | object { <key>: non-empty string | [non-empty string] } | non-empty string | [non-empty string]
   -> The entry point(s) of the compilation.
   Details:
    * configuration.entry should be an instance of function
      -> A Function returning an entry object, an entry string, an entry array or a promise to these things.
    * configuration.entry should not be empty.
      -> Multiple entry bundles are created. The key is the chunk name. The value can be a string or an array.
    * configuration.entry should be a string.
      -> An entry point without name. The string is resolved to a module which is loaded upon startup.
    * configuration.entry should be an array:
      [non-empty string]

密钥应该在configuration.entry should be one of these: function | object，但不完全知道这是什么意思...

Answer 1

问题是当我安装 webpacker (rails webpacker:install) 时，我显然已经有一个空的 app/javascript 文件夹，所以安装跳过了那些安装文件：

JavaScript 应用源目录已存在

手动添加app/javascript/packs/application.js 文件解决了这个问题。