pathisAbsolute

Path.isAbsolute, sometimes seen as pathisAbsolute in informal references, is a utility function in Node.js that determines whether a given path string refers to an absolute location on the file system. It is part of the built-in path module and helps distinguish absolute paths from relative ones. The function is available as path.isAbsolute and also in platform-specific variants path.posix.isAbsolute and path.win32.isAbsolute to reflect POSIX and Windows path rules.

The return value is a boolean: true if the input path is absolute, false otherwise. What counts as absolute depends on the platform. In POSIX, a path is absolute if it begins with a forward slash (/). In Windows, a path is absolute if it starts with a drive letter followed by a colon and a slash or backslash (for example, C:\folder), or if it begins with a UNC path (for example, \\server\share). Paths beginning with a slash or backslash are also treated as absolute under Windows semantics by the Windows-specific variant.

Usage scenarios include validating or normalizing paths before joining or resolving them and deciding whether to resolve against the current working directory. For example, path.isAbsolute('/foo/bar') yields true, while path.isAbsolute('foo/bar') yields false. When cross-platform compatibility is important, use path.posix.isAbsolute for POSIX-style paths and path.win32.isAbsolute for Windows-style paths.

See also: path.resolve, path.join, path.normalize, and the Node.js documentation for the path module.