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JSON and CSV Viewers

XeFM’s built-in file viewer can render JSON / JSON Lines files as a collapsible tree and CSV / TSV files as an aligned table, in addition to the usual raw, line-numbered text view. They work exactly like the Markdown viewer: press V to open a file, then M to toggle between the raw text and the rich view.

JSON / JSON Lines (*.json, *.jsonl, *.ndjson)

The rich view is a collapsible tree. Objects and arrays are branches you can expand and collapse; scalars are leaves. Each row shows its key (an object key or an array index) and the value, colored by type — strings, numbers, and true / false / null each get their own color, following the active theme. A collapsed branch shows its size ({3} for a 3-key object, [5] for a 5-item array), so you can see the shape of a document without expanding everything.

A .jsonl / .ndjson file (one JSON value per line) is shown as an array of its records.

Key	Action
↑ / ↓	Move up / down a row
→	Expand a branch (or step into it)
←	Collapse a branch (or jump to its parent)
Enter / Space	Toggle the selected branch
PgUp / PgDn, Home / End	Scroll by a page / jump to the top or bottom
Mouse wheel / click	Scroll / select a row (click the ▸ ▾ marker to toggle)
⌘C / Ctrl+C	Copy the selected node’s value as JSON
F	Incremental search

CSV / TSV (*.csv, *.tsv)

The rich view is an aligned table with ruled grid lines. The header row stays frozen at the top while the body scrolls, columns are sized to their content (numeric columns right-align), and the grid scrolls both vertically and horizontally so wide tables stay readable. A .tsv file is split on tabs, a .csv file on commas.

The grid lines follow the display: on the graphical app they’re crisp device-thin rules around every cell; on the terminal they’re box-drawing characters (│ column separators and a ├─┼─┤ line under the header), with the body rows zebra-striped for separation.

Key	Action
↑ / ↓ / ← / →	Move the current cell
PgUp / PgDn	Scroll a page
Home / End	First / last column
Mouse wheel	Scroll (vertical, and horizontal on a trackpad)
Click + drag	Select a rectangular block of cells
⌘C / Ctrl+C	Copy the selected cells as TSV
⌘A / Ctrl+A	Select the whole table
F	Incremental search

Shared behavior

• The M toggle and per-type memory. The rich view is reached with M, the same key the Markdown viewer uses. XeFM remembers the view you last chose per file type and reopens that type the same way next time — toggle one .json file to the tree and every .json opens as a tree afterward, this session and after a restart. The header’s top-right shows the current view’s name (JSON / Table); the footer shows the toggle key.
• Search. Press F in either rich view to search. As you type, the selection moves to the match — the current row in the JSON tree, the current cell’s row in the table — just like the main file manager’s search. In the JSON tree, matches auto-expand their branches so they’re reachable. ↑ / ↓ step between matches, Enter commits the selection on the current match, and Esc cancels and restores the selection you started from. Matching is case-insensitive.
• Malformed files fall back to raw. If a .json doesn’t parse (or a file otherwise can’t be rendered), M simply leaves you in the raw text view — which still shows the file with syntax highlighting — rather than failing.
• Both views follow the active theme and work on the terminal and the native (macOS / Windows) backends.