vim/lua/custom/plugins/nullls.lua

return {
  'jay-babu/mason-null-ls.nvim',
  lazy = false,
  -- event = { "BufReadPre", "BufNewFile" },
  dependencies = {
    'williamboman/mason.nvim',
    'jose-elias-alvarez/null-ls.nvim',
  },
  config = function()
    require('mason').setup()
    require('mason-null-ls').setup {
      ensure_installed = { 'stylua', 'jq', 'eslint_d' },
      automatic_setup = false,
      automatic_installation = false,
    }
    local nls = require 'null-ls'
    local diagnostics = nls.builtins.diagnostics
    local formatting = nls.builtins.formatting
    local code_actions = nls.builtins.code_actions
    local h = require 'null-ls.helpers'
    local u = require 'null-ls.utils'

    local function eslint_d_cwd(params)
      return u.root_pattern(
        -- https://eslint.org/docs/user-guide/configuring/configuration-files#configuration-file-formats
        '.eslintrc',
        '.eslintrc.js',
        '.eslintrc.cjs',
        '.eslintrc.yaml',
        '.eslintrc.yml',
        '.eslintrc.json'
        -- do not respect package.json
        -- "package.json",
      )(params.bufname)
    end
    require('null-ls').setup {
      debug = true,
      sources = {
        -- Anything not supported by mason.
        -- lua
        formatting.stylua,
        --json
        diagnostics.jsonlint,
        -- eslint
        diagnostics.eslint_d.with {
          cwd = h.cache.by_bufnr(eslint_d_cwd),
          -- not sure how to scope this only to bcr's locales
          -- extra_filetypes = { 'json' },
        },
        formatting.eslint_d.with {
          cwd = h.cache.by_bufnr(eslint_d_cwd),
          -- not sure how to scope this only to bcr's locales
          extra_filetypes = { 'json' },
        },
        code_actions.eslint_d.with {
          cwd = h.cache.by_bufnr(eslint_d_cwd),
          -- not sure how to scope this only to bcr's locales
          extra_filetypes = { 'json' },
        },
        -- refactoring
        code_actions.refactoring,
      },
    }
  end,
}