`tui preview` for viewers

Show text for the selected table, tree, or select row. Arrow keys stay on the source.

Flags

--from {string}: Table, tree, or select id to follow.
--max-bytes {int}: Maximum bytes to read from a file (default 65536).
--id {string}: Widget id.
--focus: Start with this widget focused.

Parameters

transform: No parameters: transform file text ($in). One parameter: produce text from the row.

Input/output types:

input	output
nothing	tui
tui	tui
any	tui

Examples

File list on the left, highlighted contents on the right

> ls | tui split [(tui table) (tui preview { nu-highlight })] | tui run

Preview a value from the row instead of a file

> $env.config.keybindings | tui split [(tui table) (tui preview {|row| $row.event | to nuon })] | tui run

Notes

Without a closure, the row's name (or the row itself when it is a string) is read as a file path, up to --max-bytes. Directories and binary files show a short note.

A closure with no parameters transforms that file text: it receives the contents as $in, with content_type in pipeline metadata, so { nu-highlight } colors source files.

A closure with one parameter is the source: it receives the selected row and whatever it returns is shown. Nothing is read from disk, so any column or computed value can be previewed: {|row| $row.event | to nuon } or {|row| open --raw $row.path }.

The preview follows the focused list, else the nearest one in the same container. --from names one explicitly.