conform.nvim configuration

Overview

conform.nvim provides fast, asynchronous code formatting with support for multiple formatters per filetype. All formatters must be installed globally. Configuration file: lua/plugins/formatter.lua:5

Installation

All formatters must be installed globally. See the installation documentation for platform-specific instructions.

Events and commands

Loading behavior

event

string[]

default:"[\"BufWritePre\"]"

Loads the plugin before writing files (for format-on-save).

cmd

string[]

default:"[\"ConformInfo\"]"

Also loads when running :ConformInfo command.

Keymaps

Manual formatting

<leader>fb

keymap

Format buffer - Manually formats the current buffer or visual selection

Modes: Normal and Visual
Async: true
Description: “[F]ormat [B]uffer”
Shows notification on successful format

function()
  require("conform").format({ async = true }, function(err, did_edit)
    if not err and did_edit then
      vim.notify("Code formatted", vim.log.levels.INFO, { title = "Conform" })
    end
  end)
end

Format-on-save

Automatic formatting

format_on_save.timeout_ms

number

default:"1000"

Maximum time (in milliseconds) to wait for formatting to complete. Aborts if exceeded.

format_on_save.lsp_format

string

default:"fallback"

Falls back to LSP formatting if no conform formatter is configured for the filetype.

Format-on-save runs synchronously with a 1-second timeout to ensure files are properly formatted before saving.

Formatter options

Biome conditional formatting

formatters['biome-check'].condition

function

The biome-check formatter only runs if a biome.json or biome.jsonc file exists in the project root.

condition = function(_, ctx)
  return vim.fs.find(
    { "biome.json", "biome.jsonc" },
    { path = ctx.filename, upward = true }
  )[1]
end

This prevents Biome from running in projects that don’t use it, improving performance.

Formatters by filetype

The configuration supports multiple formatters per filetype with fallback chains:

formatters_by_ft.lua

string[]

default:"[\"stylua\"]"

Uses stylua for Lua formatting.

All JS/TS filetypes use Biome with Prettier fallback:

formatters_by_ft.javascript

string[]

["biome-check", "prettier"] with stop_after_first = true

formatters_by_ft.javascriptreact

string[]

["biome-check", "prettier"] with stop_after_first = true

formatters_by_ft.typescript

string[]

["biome-check", "prettier"] with stop_after_first = true

formatters_by_ft.typescriptreact

string[]

["biome-check", "prettier"] with stop_after_first = true

biome-check runs biome check --write which handles:

Code formatting
Import sorting
Safe lint fixes (auto-fixable issues)

If biome.json doesn’t exist, it falls back to prettier.

formatters_by_ft.json

string[]