vallow.nvim

fallow for Neovim. See your unused code, duplicates, and health in a native split.

Powered by fallow, a sub-second static analysis engine for JS/TS. No tree-sitter, no LSP, no config needed on the Neovim side.

Requirements

• Neovim >= 0.10
• fallow CLI
• A TypeScript or JavaScript project with a package.json
• A Nerd Font if you want the icons (optional)
• nvim-web-devicons for file icons in the panel (optional)

Install

lazy.nvim

{
  "xeind/vallow.nvim",
  cmd = { "Vallow", "VallowRefresh", "VallowSearch" },
  keys = {
    { "<leader>V",  "<cmd>Vallow<cr>",        desc = "Vallow: toggle" },
    { "<leader>vr", "<cmd>VallowRefresh<cr>", desc = "Vallow: refresh" },
    { "<leader>vs", "<cmd>VallowSearch<cr>",  desc = "Vallow: search findings" },
  },
  opts = {},
}

Install fallow

npm install -g fallow      # global (recommended)
npm install --save-dev fallow  # local to project
cargo install fallow       # or via Cargo

Local install:

require("vallow").setup({ fallow_cmd = "./node_modules/.bin/fallow" })

Usage

Command	What it does
:Vallow	Toggle the panel
:VallowRefresh	Re-run fallow and refresh
:VallowSearch	Search findings with snacks / telescope / fzf-lua / vim.ui.select

Press <CR> on any issue to jump to the file and line.

Panel keymaps

All remappable via setup({ keymaps = ... }).

Key	Action
<CR>	Jump to file (edit in previous window)
o	Jump in horizontal split
v	Jump in vertical split
t	Jump in new tab
L / H	Next / previous tab (cycle sections)
]c / [c	Jump to next / previous section header
<Tab> / za	Toggle fold
zo / zc	Open / close fold
zR / zM	Open / close all folds
K	Detail float: path, name, kind, fix suggestions
f	Filter by path or name
F	Clear filter
%	Filter findings to the file under cursor
gf	Open picker (fuzzy search all findings)
P	Peek at file in floating window
Q	Send to quickfix
y	Yank path:line
r	Refresh
q	Close
?	Show keymap help

Panel structure

Sections and categories shown only when they have findings.

Section	Categories
UNUSED CODE	Unused Exports, Types, Members, Files, Dependencies, Unlisted Deps
ISSUES	Unresolved Imports, Circular Deps, Duplicate Exports
DUPLICATES	Clone Groups
HEALTH	Complexity, Hotspots, Refactoring Targets
ARCHITECTURE	Boundary Violations

Severity is color-coded: errors red, warnings yellow, hints grey.

Configuration

require("vallow").setup({
  fallow_cmd  = "fallow",
  fallow_args = {},  -- extra CLI flags forwarded verbatim

  -- Which analyses to run. Remove entries to skip them entirely.
  analyses = { "dead-code", "dupes", "health" },

  window = {
    position = "right",  -- "bottom" | "top" | "left" | "right"
    size     = 0.5,
  },

  max_items = 30,  -- items per category before "N more..." expands

  diagnostics = {
    enabled = true,
  },

  statusline = {
    prefix = "vallow ",  -- " " for a Nerd Font icon
  },

  keymaps = {
    close        = "q",
    jump         = "<CR>",
    refresh      = "r",
    toggle_fold  = nil,  -- unset by default; za/zo/zc/zR/zM always work
    next_tab     = "L",
    prev_tab     = "H",
    next_section = "]c",
    prev_section = "[c",
    filter       = "f",
    clear_filter = "F",
    pick         = "gf",
  },
})

All highlight groups (VallowHeader, VallowPath, VallowName, VallowSevError, …) link to standard Neovim groups and work with any colorscheme. Override as needed:

vim.api.nvim_set_hl(0, "VallowHeader", { fg = "#bb9af7", bold = true })

Statusline

-- lualine
require("lualine").setup({
  sections = {
    lualine_x = { { require("vallow").statusline, color = { fg = "#f9c74f" } } },
  },
})

-- raw
vim.o.statusline = "%{%v:lua.require('vallow').statusline()%}"

Shows vallow 42 when issues exist, vallow ✓ when clean, empty when not run.

Configuring fallow

vallow passes the project root to fallow. Configure fallow via .fallowrc.json:

fallow init

{
  "$schema": "https://raw.githubusercontent.com/fallow-rs/fallow/main/schema.json",
  "entry": ["src/index.ts"],
  "ignorePatterns": ["**/*.test.ts", "dist/**"],
  "ignoreDependencies": ["typescript"],
  "rules": {
    "unused-export": "error",
    "unused-file": "warn",
    "circular-dependency": "warn"
  }
}

Suppress findings inline:

// fallow-ignore-next-line unused-export
export function keepThisPublic() {}

License

MIT