README

JSON Tab WLX for Lazarus/FPC

JSON Tab WLX is a native Windows Lister plugin for Total Commander that displays JSON documents as a combined tree, table, and formatted text view.

Both regular JSON documents (.json) and JSON Lines documents (.jsonl) are supported. JSONL records are shown as the elements of one root array and are saved back as one compact JSON value per line.

This project is a Lazarus/Free Pascal migration of the original jsontab-wlx plugin by little-brother. The original program established the user interface, behavior, and core feature set on which this port is based.

The migration keeps the familiar workflow and turns it into a faster, more interactive JSON workbench for Total Commander.

Feature Highlights

JSON Tab WLX is built for the moment when a JSON file is too structured for a plain text viewer, but too quick-and-dirty for a full editor. Open it in Lister, jump through the tree, flatten useful structures into columns, filter the result, edit a scalar value, copy exactly what you need, and move on.

• Tree, table, and text at once: browse objects and arrays in the tree, inspect rows in the grid, and switch to syntax-highlighted formatted JSON when the raw structure matters.
• JSONL feels like normal JSON: .jsonl files are shown as one root array, while saving keeps the compact one-record-per-line format.
• Flat views for nested data: FlatViewLevel unfolds nested objects and arrays into practical columns such as message, meta.message, or modulation_params.audio_freq. Homogeneous scalar matrices are displayed with one index column per inner-array position. Optional missing leaf fields are filled with the configured placeholder. The status bar marks exact matches as Flat: 1+ and softened matches as Flat: 1*.
• Filters that stay usable: every column can be filtered with substring matching or operators like =, !, <, and >. The filter row follows horizontal scrolling and column resizing smoothly, so it keeps feeling like part of the grid.
• Sorting that understands data: JSON numbers sort numerically, embedded numbers sort naturally, and text sorting uses Windows locale-aware comparison. A third click restores the original order.
• Readable numbers, even in proportional fonts: decimal alignment is enabled by default. Decimal separators line up per column, and integers sit correctly at the same numeric anchor.
• Fast on large arrays: the grid is virtual and keeps filtering/sorting in a result index instead of rearranging the JSON data itself.
• Inline editing when you need it: toggle edit mode with Ctrl+E, edit scalar cells directly, insert structurally matching rows, delete rows or columns, and save back with Ctrl+S.
• Keyboard-friendly grid work: arrow keys move the current cell, scrolling the view at the edges; Ctrl+Arrow jumps to the first or last row/column.
• Useful right-click tools: copy cells, rows, columns, JSONPath, or inferred JSON; hide columns; restore all columns; select the corresponding tree item.
• Comfort details: automatic column sizing, alternating row colors, current-cell highlighting, light/dark themes, configurable colors, UTF-8 and UTF-16 detection, plus native Win32 and Win64 WLX builds without the LCL runtime.

Editing

Press Ctrl+E or use Edit mode in the grid context menu to toggle editing. While edit mode is active, double-clicking a scalar cell opens an inline editor.

• Enter or focus loss accepts an edit
• Escape cancels the active edit
• Ctrl+S saves modified JSON back to the source file
• Unsaved changes are marked in the status bar
• The detected source-file encoding is retained when saving
• Floating-point JSON values with a zero fractional part retain their decimal form, for example 10000000.0

Arrays and objects remain read-only as cells; edit their scalar descendants instead.

Keyboard And Mouse

Additional Total Commander Lister keys are forwarded to the host where supported.

Context Menu

Right-click the grid to access:

• Copy
• Copy row(s) (Shift+C)
• Copy column (Ctrl+C)
• Copy as JSON
• Copy JSONPath
• Hide column
• Show all columns (Ctrl+Space)
• Filters
• Edit mode (Ctrl+E)
• Theme: Total Commander, light, or dark

Installation

Use the build matching your Total Commander installation:

• jsontab.wlx64 for 64-bit Total Commander
• jsontab.wlx for 32-bit Total Commander

Install the file as a Total Commander Lister plugin through:

Configuration > Options > Plugins > Lister plugins

The default detection string handles files with the .json and .jsonl extensions.

Building

Requirements:

• Lazarus with Free Pascal 3.2.2 or compatible
• Windows target support for Win32 and/or Win64

Open jsontab.lpi in Lazarus and select one of the supplied build modes:

• Release 64, producing jsontab.wlx64
• Release 32, producing jsontab.wlx

Command-line builds:

lazbuild jsontab.lpi --build-mode="Release 64"
lazbuild jsontab.lpi --build-mode="Release 32"

Configuration

If an INI file exists beside the WLX plugin, it takes precedence over the default plugin INI path supplied by Total Commander. Otherwise, the supplied path is used. If Total Commander supplies no path, the INI beside the plugin is used and created when settings are written.

Inline comments are supported when separated from the value by whitespace:

font-size=16 ; use a larger font

Settings belong in the [jsontab] section.

The plugin stores the selected tab, splitter position, filter-row visibility, font size, and theme mode. It also supports configuration values inherited from the original plugin, including colors, filter behavior, font settings, missing-value text, parsing limits, and the detection string.

Dark Mode

Use theme-mode to select how the plugin chooses its colors:

[jsontab]
theme-mode=tc       ; follow Total Commander (default)
; theme-mode=light  ; always use the plugin's light colors
; theme-mode=dark   ; always use the plugin's dark colors

• tc follows Total Commander through its ListSendCommand notifications. Switching Total Commander between light and dark mode immediately updates an open Lister window. On Windows 10/11, Total Commander's native-dark-mode flag is also used for controls that support native dark rendering.
• light and dark are persistent plugin choices. Theme changes in Total Commander do not override them.
• For older INI files without theme-mode, dark-theme=0 selects light and dark-theme=1 selects dark. Once theme-mode is present, it takes precedence.

The usual color settings have a -dark counterpart, for example back-color-dark, back-color2-dark, text-color-dark, filter-back-color-dark, and filter-text-color-dark. They use Windows COLORREF decimal values, as shown in jsontab_default.ini.

Language

language=Auto follows Total Commander's configured language when a matching catalog is available and otherwise uses the Windows UI language. A language can also be selected explicitly, for example language=de or language=en. If no matching catalog is available, the plugin falls back to English.

English, German, Czech, Russian, and Ukrainian catalogs are included in the language directory. Additional UTF-8 catalogs can be added as language/<code>.lng; regional codes such as de-DE fall back to de.lng. Missing catalogs or individual entries fall back to the English strings built into the plugin.

Original layout and interaction settings are supported as well:

• alwaysStartAtRoot: always select <<root>> when loading (0/1, default 0). With 0, the normal startup-selection rules apply.
• copy-column: copy the current column with plain C when multiple rows are selected
• decimal-align: align decimal values with , or . at their decimal separator and right-align signed or unsigned integers (0/1, default 1). In columns containing both integers and decimals, integers end directly at the shared decimal anchor.
• disable-grid-lines: hide grid lines
• filter-align: align filter text left (-1), centered (0), or right (1)
• language: Auto or a language code such as en, de, cs, ru, or uk
• font-weight: select a font weight from 0 through 9
• max-column-width: limit automatic multi-column sizing; in two-column grids only the first column is capped, while the second uses its full measured header/content width

Decimal alignment measures the integer part using the active grid font, so it also works with proportional fonts. Non-numeric values and values containing multiple decimal separators retain their normal display.

Tests

• tests/decimal_align_test.lpr verifies decimal and integer recognition.
• tests/jsonl_model_test.lpr verifies JSONL loading and saving.
• tests/wlx_viewer_test.lpr loads the compiled WLX and exercises decimal owner-draw after filtering, sorting, font zoom, editing, and structural tree changes.

Original Project

Original jsontab-WLX project: github.com/little-brother/jsontab-wlx

Please refer to the original repository for its history, documentation, issue tracker, and releases.