The `vue-cli-service serve` command starts a dev server (based on [webpack-dev-server](https://github.com/webpack/webpack-dev-server)) that comes with Hot-Module-Replacement (HMR) working out of the box.
In addition to the command line flags, you can also configure the dev server using the [devServer](https://cli.vuejs.org/config/#devserver) field in `vue.config.js`.
k`[entry]` in the CLI command is defined as _the entry file_ (default: `src/main.js` or `src/main.ts` in TypeScript project), not _an additional entry file_. If you overwrite the entry in the CLI, then the entries from `config.pages` are no longer considered, which may cause an error.
vue-cli-serviceのserveはwebpack-dev-serverをベースにしたhmr(hot module replacement)、キャッシュなどを効かせた状態でサーバーを立ち上げる。 webpack-dev-serverはes2015にトランスパイルされるみたい