Avoid adding reactive properties to a Vue instance or its root $data at runtime - declare it upfront in the data option.

非常好的问题！这是一个非常重要的Vue.js最佳实践。Vue.js的响应式系统是基于对象的getter/setter拦截实现的，这意味着只有在Vue实例被创建时定义的属性才能被Vue追踪。如果在运行时动态添加属性，Vue将无法检测到它们的变化，并且可能会导致一些不可预测的行为。

因此，Vue.js官方文档建议在定义Vue实例或组件时，应该提前声明所有可能被使用的属性，并将它们初始化为合适的默认值。这可以通过在Vue实例或组件的"data"选项中声明属性来完成。

如果您需要在运行时动态添加属性或修改属性值，请使用Vue.set或Vue.$set方法。这些方法将确保新属性被Vue追踪，并且在DOM更新时被正确处理。

相关问题

vendor.js?t=wechat&s=1685285249979&v=56cc1d782ac90c11e54dc8dddf458353:4015 [Vue warn]: Avoid adding reactive properties to a Vue instance or its root $data at runtime - declare it upfront in the data option.(env: Windows,mp,1.06.2303220; lib: 2.31.1)

这是一个Vue.js的警告信息，告诫开发者不要在运行时将响应式属性添加到Vue实例或其根$data中，而是应该在data选项中提前声明。这是为了确保Vue能够正确地追踪哪些属性是响应式的，并在数据更改时更新相关组件。如果在运行时添加响应式属性，可能会导致Vue无法正确地追踪更改并更新组件。该警告信息还提供了环境信息和Vue.js的版本信息。

WARNING: The script wheel.exe is installed in 'C:\Users\86136\AppData\Roaming\Python\Python39\Scripts' which is not on PATH. Consider adding this directory to PATH or, if you prefer to suppress this warning, use --no-warn-script-location. WARNING: The script f2py.exe is installed in 'C:\Users\86136\AppData\Roaming\Python\Python39\Scripts' which is not on PATH. Consider adding this directory to PATH or, if you prefer to suppress this warning, use --no-warn-script-location. WARNING: The script normalizer.exe is installed in 'C:\Users\86136\AppData\Roaming\Python\Python39\Scripts' which is not on PATH. Consider adding this directory to PATH or, if you prefer to suppress this warning, use --no-warn-script-location. WARNING: The scripts pyrsa-decrypt.exe, pyrsa-encrypt.exe, pyrsa-keygen.exe, pyrsa-priv2pub.exe, pyrsa-sign.exe and pyrsa-verify.exe are installed in 'C:\Users\86136\AppData\Roaming\Python\Python39\Scripts' which is not on PATH. Consider adding this directory to PATH or, if you prefer to suppress this warning, use --no-warn-script-location. WARNING: The script markdown_py.exe is installed in 'C:\Users\86136\AppData\Roaming\Python\Python39\Scripts' which is not on PATH. Consider adding this directory to PATH or, if you prefer to suppress this warning, use --no-warn-script-location. WARNING: The script google-oauthlib-tool.exe is installed in 'C:\Users\86136\AppData\Roaming\Python\Python39\Scripts' which is not on PATH. Consider adding this directory to PATH or, if you prefer to suppress this warning, use --no-warn-script-location. WARNING: The script tensorboard.exe is installed in 'C:\Users\86136\AppData\Roaming\Python\Python39\Scripts' which is not on PATH. Consider adding this directory to PATH or, if you prefer to suppress this warning, use --no-warn-script-location.

这些警告是因为你在安装某些 Python 包时，它们在安装过程中将可执行文件安装到了 Python 的 `Scripts` 文件夹中，但是这个文件夹不在系统的 `PATH` 环境变量中，因此可能无法直接运行这些可执行文件。

你可以将 `C:\Users\86136\AppData\Roaming\Python\Python39\Scripts` 添加到系统的 `PATH` 环境变量中，这样就可以直接在命令行中运行这些可执行文件了。或者，你可以使用 `--no-warn-script-location` 选项来忽略这些警告。