VizFlow
VizFlow is a Visual Studio Code extension for exploring, transforming, and visualizing CSV data — without ever leaving your editor.
Open a CSV file, run a command from the Command Palette, and get instant results: aggregations, duplicate reports, column statistics, a full visual transformation studio, side-by-side CSV comparison, an interactive chart builder, a dataset summary dashboard, a full SQL-like RBQL query console, and more — all in one place.
✨ Features at a Glance
| Category |
What you can do |
| Aggregations |
Sum, Average, Min, Max, Count on any column |
| Data Quality |
Find duplicate values with exact row locations |
| Profiling |
Full column statistics (count, sum, avg, min, max, duplicates) |
| Exploration |
List all distinct values in a column |
| Transformation (CLI) |
Apply one operation to a column via Command Palette prompts |
| Transformation (Visual) |
Multi-rule transformation studio in a side panel — preview, reorder, target specific rows, and save |
| CSV Comparison |
Side-by-side column comparison across two files with match / only-A / only-B breakdown |
| Dataset Dashboard |
At-a-glance summary of every column — types, nulls, distinct counts, and top values |
| Interactive Charts |
Plot your CSV data as bar, line, pie, scatter, and more in a live chart panel |
| RBQL Query Console |
Write and execute SQL-like RBQL queries against your CSV with syntax highlighting, query history, and CSV/JSON export |
| About / Creator |
View creator info and project links directly inside VS Code |
🚀 Quick Start
- Open any CSV file in VS Code.
- Press
Ctrl+Shift+P (or Cmd+Shift+P on macOS) to open the Command Palette.
- Type VizFlow and choose any command.
All results appear in the dedicated VizFlow Output panel or a WebView panel depending on the command.
📋 Commands
Aggregations
| Command |
Description |
VizFlow: Sum Column |
Adds up all numeric values in the selected column |
VizFlow: Average Column |
Calculates the mean of all numeric values |
VizFlow: Minimum Value |
Finds the smallest value in a column |
VizFlow: Maximum Value |
Finds the largest value in a column |
VizFlow: Count Values |
Counts non-empty values in a column |
Data Quality & Profiling
| Command |
Description |
VizFlow: Find Duplicate Values |
Lists every duplicate value, its count, and the exact row numbers where it appears |
VizFlow: Show Column Statistics |
Shows count, sum, average, min, max, duplicate count, and duplicate row count in one shot |
VizFlow: Show Distinct Values |
Lists every unique value in the selected column along with the total distinct count |
| Command |
Description |
VizFlow: Transform Column |
Command-line workflow — pick column → operation → parameters → preview 5 rows → apply to all |
VizFlow: Transform Column (Visual) |
Opens the Visual Transformation Studio as a side panel |
Comparison
| Command |
Description |
VizFlow: Compare CSV Files |
Select a column in the active CSV and compare it against a column in a second CSV file. Results are grouped into common, only in File A, and only in File B values, each with exact row numbers and column profiles |
Visualization & Analysis
| Command |
Description |
VizFlow: Dataset Summary Dashboard |
Opens a rich WebView dashboard with per-column type inference, null counts, distinct counts, and top-value charts |
VizFlow: Interactive Charts |
Opens a chart builder — choose chart type, X/Y axes, and render a live interactive chart from your CSV data |
RBQL Query Console
| Command |
Description |
VizFlow: RBQL Query Console |
Opens a full SQL-like query console powered by RBQL. Write queries with syntax highlighting, execute against your CSV, browse query history, and export results to CSV or JSON |
General
| Command |
Description |
VizFlow: About / Creator |
Opens a WebView panel with information about the extension creator |
The Visual Transformation Studio (VizFlow: Transform Column (Visual)) opens a dedicated WebView panel beside your CSV file and lets you build, preview, and apply a queue of transformation rules.
Workflow
Add a rule → Add more rules → Preview → Apply & Save
- Select a column from the dropdown.
- Choose an operation — grouped by Numeric, String, or Conditional.
- Fill in parameters (inputs appear dynamically based on the chosen operation).
- Choose scope — apply to All rows or Selected rows only (individual numbers or ranges like
5-8).
- Click ➕ Add Rule — the rule appears as a numbered card in the queue.
- Repeat steps 1–5 to add as many rules as needed. Reorder them with ↑ ↓, or remove with ✕.
- Click 👁️ Preview (5 rows) — see a before/after table for the first 5 rows, for every rule in sequence.
- Click ✅ Apply & Save — all rules are applied to the full dataset, results are written to the Output Channel, and a native Save dialog opens pre-filled with
<original-name>_transformed.csv.
Numeric
| Operation |
Description |
| Add (+) |
Adds a constant to every value |
| Subtract (−) |
Subtracts a constant |
| Multiply (×) |
Multiplies by a constant |
| Divide (÷) |
Divides by a constant (guards against division by zero) |
| Power (^) |
Raises every value to an exponent |
| Round |
Rounds to N decimal places |
| Absolute Value |
Removes the sign from every number |
String
| Operation |
Description |
| UPPER CASE |
Converts every value to upper case |
| lower case |
Converts every value to lower case |
| Trim whitespace |
Strips leading and trailing spaces |
| Concat (append) |
Appends a fixed string to each value |
| Substring |
Extracts characters from a start index, with optional length |
| Replace |
Replaces every occurrence of a search string |
| Length (char count) |
Replaces the value with its character count |
| Pad Start (left) |
Left-pads to a target width with a chosen character |
| Pad End (right) |
Right-pads to a target width with a chosen character |
Conditional
| Operation |
Description |
| Coalesce (fallback) |
Replaces blank or null values with a fallback |
| Starts With (check) |
Returns true/false — does the value start with a prefix? |
| Ends With (check) |
Returns true/false — does the value end with a suffix? |
| Contains (check) |
Returns true/false — does the value contain a substring? |
Every rule in the queue can target all rows or a subset of rows:
- Select Selected rows only in the Apply to toggle.
- Enter row numbers or ranges in the Row numbers field — e.g.
1, 3, 5-8, 10.
- Row 1 = first data row (header is not counted).
- Rows outside the selection are passed through unchanged. The preview table marks them as (skipped).
- Rules with different scopes can be mixed in the same queue — e.g. uppercase column A for all rows, then multiply column B only for rows 5 and 10.
🔍 CSV Comparison
The Compare CSV Files command (VizFlow: Compare CSV Files) lets you pick one column from the currently open CSV and compare it against a column from any other CSV file on disk.
How it works
- Run
VizFlow: Compare CSV Files with a CSV open in the editor.
- Select the column to compare from the active file (File A).
- Pick the second CSV file from a file-open dialog.
- Select the column to compare from File B.
- A WebView panel opens with a full side-by-side report:
| Section |
What it shows |
| Summary bar |
Total rows, match count, only-A count, only-B count |
| Column profiles |
Distinct count, null count, inferred data type for each column |
| Results table |
Every distinct value labelled common, only A, or only B, with row-number lists for both files |
The comparison is value-based (set logic) — row order and row count don't matter, only whether the value exists in each file's column.
🔎 RBQL Query Console
The RBQL Query Console (VizFlow: RBQL Query Console) brings a full SQL-like query experience to your CSV data, powered by the RBQL engine.
Features
- Syntax-highlighted editor — keywords, functions, strings, numbers, and operators each render in a distinct colour with a VS Code–styled gutter.
- Query history — previously run queries are saved and can be re-selected with a single click.
- Progress indicator — a live progress bar tracks execution on large files.
- Export — download results as CSV or JSON directly from the results panel.
Example queries
SELECT * WHERE a1 == 'Sales' ORDER BY a2 DESC LIMIT 100
SELECT a1, COUNT(*) GROUP BY a1
SELECT * WHERE parseInt(a3) > 500 AND a4 LIKE '%active%'
Column naming: RBQL uses a1, a2, … for columns by index. Enable Has Header Row to also reference columns by name.
📊 Interactive Charts
The Interactive Charts panel (VizFlow: Interactive Charts) lets you visualize your CSV data without leaving VS Code.
- Choose from bar, line, pie, scatter, and other chart types.
- Map any CSV columns to the X and Y axes.
- Charts render live inside a WebView panel with full interactivity.
🗂️ Architecture
vizflow/
├── extension.js # Entry point — registers all commands
├── commands/
│ ├── sum.js # Aggregation commands
│ ├── average.js
│ ├── aggregate.js # Shared min / max / count handler
│ ├── statistics.js
│ ├── duplicate.js
│ ├── distinctValues.js
│ ├── transform.js # CLI-based transform workflow
│ ├── transformWebview.js # Visual Transformation Studio host
│ ├── compareCSV.js # CSV Comparison WebView host
│ ├── dashboard.js # Dataset Summary Dashboard host
│ ├── charts.js # Interactive Charts WebView host
│ ├── rbql.js # RBQL Query Console WebView host
│ └── about.js # About / Creator WebView panel
├── engine/
│ ├── dataset.js # Dataset model (rows, columns, profiling)
│ ├── duplicateFinder.js # Duplicate detection engine
│ ├── expressions/
│ │ ├── operations.js # 20 pure transform functions + metadata catalogue
│ │ └── evaluator.js # evaluate() / evaluateRows() / previewFirst()
│ ├── aggregations/ # Sum, average, distinct, statistics engines
│ └── profiler/ # Column profiler
├── services/
│ ├── csvReader.js # Reads the active editor's CSV text
│ ├── csvParser.js # PapaParse wrapper with type inference
│ ├── csvCompare.js # Pure comparison engine (no VS Code deps)
│ └── output.js # Shared VizFlow Output Channel helpers
└── media/
├── transform.html / .css # Visual Transformation Studio
├── compare.html / .css # CSV Comparison
├── dashboard.html / .css # Dataset Summary Dashboard
├── charts.html / .css # Interactive Charts
├── rbql.html / .css # RBQL Query Console
└── rbql-syntax.js # Client-side RBQL syntax highlighter
⚙️ Requirements
- VS Code
1.125.0 or newer
- A CSV file open as the active editor when running any command
No other tools, runtimes, or accounts are needed. Everything runs locally.
📦 Installation
From the VS Code Marketplace
Search for VizFlow in the Extensions view (Ctrl+Shift+X) and click Install.
From a .vsix file
code --install-extension vizflow-0.0.2.vsix
From source
git clone https://github.ibm.com/Aditya-Mukherjee1/VizFlow.git
cd VizFlow
npm install
# Press F5 in VS Code to launch the Extension Development Host
🛠️ Development
# Install dependencies
npm install
# Run lint
npm run lint
# Run tests
npm test
The extension uses PapaParse for CSV parsing and RBQL for query execution, and has no other runtime dependencies.
🗺️ Roadmap
- [x] Dataset Summary view (row count, column types, null counts)
- [x] SQL-like query support via RBQL Query Console
- [x] Charts & visualizations
- [ ] Data Quality Report across all columns
- [ ] Remove / deduplicate rows
- [ ] Export results to a new CSV directly from the Output panel
- [ ] Multi-file join support in the RBQL console
📄 License
MIT — see LICENSE for details.
Built with ❤️ for data engineers, analysts, and anyone who works with CSV files in VS Code.
Aditya Mukherjee · Application Developer — Azure Cloud FullStack · IBM
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