文件访问的常量

以下常量旨在与 fs.access() 一起使用。

常量	描述
`F_OK`	指示文件对调用进程可见的标志。这对于确定文件是否存在很有用，但没有说明 `rwx` 权限。未指定模式时的默认值。
`R_OK`	指示文件可以被调用进程读取的标志。
`W_OK`	指示文件可以被调用进程写入的标志。
`X_OK`	指示文件可以被调用进程执行的标志。这在 Windows 上不起作用（行为类似于 `fs.constants.F_OK`）。

The following constants are meant for use with fs.access().

Constant	Description
`F_OK`	Flag indicating that the file is visible to the calling process. This is useful for determining if a file exists, but says nothing about `rwx` permissions. Default if no mode is specified.
`R_OK`	Flag indicating that the file can be read by the calling process.
`W_OK`	Flag indicating that the file can be written by the calling process.
`X_OK`	Flag indicating that the file can be executed by the calling process. This has no effect on Windows (will behave like `fs.constants.F_OK`).