If you are upgrading the vUE package in your project from version 3 to version 4, for example:

"@ vue/cli - plugin - Babel" : "^ 4.5.12", "@ vue/cli - plugin - eslint" : "^ 4.5.12", "@ vue/cli - plugin - unit - mocha" : "^ 4.5.12," "@ vue/cli - service" : "^ 4.5.12",Copy the code

As in V4, ESLint needs to be a dependency on the project itself, so you need to install two esLint-related packages to fix this warning. You need to install two third-party packages as follows:

NPM install — save-dev eslint@4 NPM install — save-dev eslint-plugin-vue