官方：暂不支持

自己弄，解决方案：

1. 安装插件

cnpm i open-browser-webpack-plugin -D

2. .umirc.ts

import { defineConfig } from ‘umi‘;

export default defineConfig({
  chainWebpack(memo, { env, webpack, craeteCSSRule }) {
    env === ‘development‘
      ? memo
        .plugin(‘open-browser-webpack-plugin‘)
        .use(‘open-browser-webpack-plugin‘, [{ url: ‘http://localhost:8000‘ }])
      : ‘‘; // 此处URL与项目启动的URL保持一致
  },
  nodeModulesTransform: {
    type: ‘none‘,
  },
  routes: [
    { path: ‘/‘, component: ‘@/pages/index‘ },
  ],
  fastRefresh: {},
});

React丨Umi3.x 启动后自动打开浏览器