vant/packages/vant-cli/src/commands/dev.ts

import webpack from 'webpack';
import WebpackDevServer from 'webpack-dev-server';
import { getPort } from 'portfinder';
import { clean } from '../commands/clean';
import { buildESModuleOutputs } from './build';
import { siteDevConfig } from '../config/webpack.site.dev';
import { genPackageEntry } from '../compiler/gen-package-entry';
import { genPacakgeStyle } from '../compiler/gen-package-style';
import { genMobileEntry } from '../compiler/gen-mobile-entry';
import { genDesktopEntry } from '../compiler/gen-desktop-entry';
import { genDepsMap } from '../compiler/gen-style-deps-map';

function runWebpack() {
  const server = new WebpackDevServer(
    webpack(siteDevConfig),
    (siteDevConfig as any).devServer
  );

  getPort(
    {
      port: 8080
    },
    (err, port) => {
      if (err) {
        console.log(err);
        return;
      }

      server.listen(port, 'localhost', (err?: Error) => {
        if (err) {
          console.log(err);
        }
      });
    }
  );
}

export async function dev() {
  await clean();
  await buildESModuleOutputs();
  genDepsMap();
  genPackageEntry();
  genPacakgeStyle();
  genMobileEntry();
  genDesktopEntry();
  runWebpack();
}