isdirectory

IsDirectory is a common function or method in many programming languages that determines whether a given path refers to a directory in the file system. It typically returns a boolean value: true when the path designates a directory, and false when it designates a regular file, a non-existent path, or another kind of filesystem object. In some environments, the check may follow symbolic links to report the type of the link’s target, while in others it may report the link itself as a separate type or require an explicit option to follow links.

How it works in practice varies by language and API. Most implementations first obtain the file system metadata for the path (for example, via a stat-like call) and then inspect the file type attribute to determine if it is a directory. If the path does not exist, or if the running process lacks sufficient permissions, the function may throw an exception, return false, or signal an error, depending on the language's conventions.

Common usage of isDirectory includes validating input before listing contents, reading directory entries, or performing recursive operations where directory traversal is required. It is often paired with a complementary check for files or with methods that list directory contents.

Examples across languages illustrate the variety of APIs. In Node.js, a path can be checked with a metadata object’s isDirectory() method. Python provides os.path.isdir(path). Java uses File.isDirectory(), and C# commonly relies on Directory.Exists(path) to confirm a path refers to a directory. Different environments have different edge cases, such as handling symbolic links, permissions, and platform-specific path semantics.