Today, I reported an error with webpack dev server in the project to visually check the version problem
the webpack version used in the project is "webpack": "^ 4.28.4"
the default is "webpack dev server": "^ 4.7.3" , and the reduced version is "webpack dev server": "^ 3.1.14" . The problem is solved

Then start the error report:
check the data and find that the startup command is changed to NPX webpack server -- config webpack dev.js