fallow viz

See where dead code, duplication, boundary violations, and complexity sit in your codebase. Fallow viz writes one self-contained HTML map with a file treemap and an import graph.

Use fallow viz to see where the findings sit in your codebase, and to click from a finding to the evidence behind it. The command runs one project analysis and writes one self-contained HTML file. The file needs no server and no external assets, and it has the same style as the rest of fallow. fallow viz is read-only.

fallow viz                       # writes fallow-viz.html and opens it in your browser
fallow viz --out map.html --no-open
fallow viz --viz-format dot      # emit the import graph as Graphviz DOT
fallow viz --viz-format mermaid  # emit the import graph as a Mermaid diagram

The two views

The HTML map has two views of the same project:

• Treemap of files sized by bytes, nested by directory.
• Force-directed import graph, with clusters by directory and by import community. When you focus a file, an import that loads its target only on demand (import(), a lazy glob, a worker) has a dashed line.

The four lenses

Each lens gives the map different colors. The two views share the four lenses:

Click a file to open a detail panel. The panel shows the evidence behind each finding:

• unused export names
• clone groups and their other locations
• boundary crossings
• cycle membership
• importers and imports, as links to click through
• a fallow ... --trace command that you can run to verify the finding

The map also has search, breadcrumb drill-down, keyboard shortcuts, shareable URL deep links, and dark and light themes. Findings have a hatch texture and an [E] or [W] prefix, so color is never the only signal. All motion follows prefers-reduced-motion.

Options

Global flags such as --root, --config, --production, --no-cache, --changed-since, --workspace, and --threads also apply.

Text formats

To pipe the import graph into other tools, use --viz-format dot or --viz-format mermaid. Fallow then writes the graph as text, and does not write the HTML map:

fallow viz --viz-format dot | dot -Tsvg -o graph.svg
fallow viz --viz-format mermaid > graph.mmd

See also