foldlevel

Foldlevel is a numeric setting used by text editors and integrated development environments to control how code folds are displayed. Code folding allows blocks of text to be collapsed into a single line or summary, helping users manage large files by focusing on structure rather than details. Foldlevel determines how deep nested fold regions should be expanded when a file is opened or the editor refreshes its view; folds deeper than the specified level are collapsed. While the core idea is consistent, the precise interpretation and default values can vary between editors and folding methods.

In editors that support explicit folding methods—such as Vim with foldmethod (manual, syntax, indent, marker, etc.)—foldlevel works in concert with those methods. It typically affects which folds are open by default after loading a file. A higher foldlevel reveals more nested content, while a lower foldlevel hides more of the folds. Some environments also provide a foldlevelstart setting to influence initial visibility when reopening a file. Users can usually override the default by issuing commands to adjust the foldlevel or by manually opening and closing folds (for example, through keyboard shortcuts or on-screen controls).

The concept is generally display-oriented: foldlevel does not alter the underlying text, only its presentation. Changes to the folding method or to the structure of the file can change how fold levels are computed. In some systems, folds may be stored in the file or computed on the fly, which can affect consistency across sessions.

See also: foldmethod, foldexpr, foldtext.