Bufferlocal

Bufferlocal refers to data that is scoped to a single buffer in text editors such as Vim and Neovim. In this context, a buffer-local value is stored and used only while that particular buffer is loaded, and other buffers have their own separate values. This allows per-buffer customization and state without affecting other buffers.

In Vim and Neovim, buffer-local data is most commonly implemented in two ways. First, there are buffer-local variables stored in the b: namespace. These variables exist only for the current buffer. For example, one might set let b:my_toggle = 1 to enable a feature for the current buffer. They can be read with exists('b:my_toggle') or retrieved via getbufvar(bufnr('%'), 'my_toggle', 0). Second, many editor options can be made buffer-local with the setlocal command. For instance, setlocal tabstop=4 and setlocal shiftwidth=4 apply only to the active buffer, leaving other buffers unchanged.

Buffer-local data persists for as long as the buffer is loaded. Switching to another buffer uses that buffer’s own values, and re-entering the original buffer restores its local state. When buffers are unloaded or the editor exits, buffer-local variables and per-buffer options are discarded unless saved elsewhere.

Common use cases include per-filetype customization, per-buffer toggles, and temporary state that should not leak across buffers. For example, a plugin might set b:my_plugin_enabled in a buffer to enable specialized behavior only for that file, or a script may apply setlocal options to ensure consistent formatting when editing a specific kind of file.

Compared with window-local (w:) or global (g:) scope, bufferlocal provides a middle ground: behavior and data that are isolated to a specific buffer but shared across all windows displaying that buffer.