Browserslist: caniuse-lite is outdated. Please run: npx update-browserslist-db@latest Why you should do it regularly: https://github.com/browserslist/update-db#readme Though the "loose" option was set to "false" in your @babel/preset-env config, it will not be used for @babel/plugin-proposal-private-property-in-object since the "loose" mode option was set to "true" for @babel/plugin-proposal-class-properties. The "loose" option must be the same for @babel/plugin-proposal-class-properties, @babel/plugin-proposal-private-methods and @babel/plugin-proposal-private-property-in-object (when they are enabled): you can silence this warning by explicitly adding ["@babel/plugin-proposal-private-property-in-object", { "loose": true }] to the "plugins" section of your Babel config.

这是一条警告信息，告诉你需要更新你的浏览器兼容性列表。更新后，你可以更好地支持最新的浏览器特性。另外，这还提醒你在使用 @babel/preset-env 时，需要保持插件的 "loose" option 一致，否则会出现这个警告。你可以在 Babel 配置文件的 "plugins" 部分中添加 ["@babel/plugin-proposal-private-property-in-object", { "loose": true }] 来解决这个问题。