Customize cmp Completion

Customize Keybindings

Some overrides require access to the plugin itself that you are overriding. This comes up a lot in things adding custom mappings to cmp. This can be achieved with the following in your user/init.lua:

return {
  plugins = {
    { -- override nvim-cmp plugin
      "hrsh7th/nvim-cmp",
      -- override the options table that is used in the `require("cmp").setup()` call
      opts = function(_, opts)
        -- opts parameter is the default options table
        -- the function is lazy loaded so cmp is able to be required
        local cmp = require "cmp"
        -- modify the mapping part of the table
        opts.mapping["<C-x>"] = cmp.mapping.select_next_item()

        -- return the new table to be used
        return opts
      end,
    },
  },
}

Customize Source Priority

Similarly to customizing mappings, you can customize and configure your cmp sources as well:

return {
  plugins = {
    { -- override nvim-cmp plugin
      "hrsh7th/nvim-cmp",
      -- override the options table that is used in the `require("cmp").setup()` call
      opts = function(_, opts)
        -- opts parameter is the default options table
        -- the function is lazy loaded so cmp is able to be required
        local cmp = require "cmp"
        -- modify the sources part of the options table
        opts.sources = cmp.config.sources {
          { name = "nvim_lsp", priority = 1000 },
          { name = "luasnip", priority = 750 },
          { name = "buffer", priority = 500 },
          { name = "path", priority = 250 },
        }

        -- return the new table to be used
        return opts
      end,
    },
  },
}

Modify Existing Source Options

You can use this cmp override to also customize the options of the sources:

return {
  plugins = {
    { -- override nvim-cmp plugin
      "hrsh7th/nvim-cmp",
      -- override the options table that is used in the `require("cmp").setup()` call
      opts = function(_, opts)
        -- opts parameter is the default options table
        -- the function is lazy loaded so cmp is able to be required
        local cmp = require "cmp"
        -- modify the sources part of the options table
        opts.sources = cmp.config.sources {
          { name = "nvim_lsp", priority = 1000 },
          { name = "luasnip", priority = 750 },
          {
            name = "buffer",
            priority = 500,
            option = {
              get_bufnrs = function() return vim.api.nvim_list_bufs() end,
            },
          },
          { name = "path", priority = 250 },
        }

        -- return the new table to be used
        return opts
      end,
    },
  },
}

Add More Sources

To add more sources than the default, you can add other cmp source plugins as dependencies, and then add the new source in the opts:

return {
  plugins = {
    { -- override nvim-cmp plugin
      "hrsh7th/nvim-cmp",
      dependencies = {
        "hrsh7th/cmp-emoji", -- add cmp source as dependency of cmp
      },
      -- override the options table that is used in the `require("cmp").setup()` call
      opts = function(_, opts)
        -- opts parameter is the default options table
        -- the function is lazy loaded so cmp is able to be required
        local cmp = require "cmp"
        -- modify the sources part of the options table
        opts.sources = cmp.config.sources {
          { name = "nvim_lsp", priority = 1000 },
          { name = "luasnip", priority = 750 },
          { name = "buffer", priority = 500 },
          { name = "path", priority = 250 },
          { name = "emoji", priority = 700 }, -- add new source
        }

        -- return the new table to be used
        return opts
      end,
    },
  },
}

Advanced Setup For Filetype and Cmdline

You can also use the config function and the provided default configuration function for each plugin to extend the configuration and setup of cmp like adding cmp-cmdline:

return {
  plugins = {
    {
      { -- override nvim-cmp plugin
        "hrsh7th/nvim-cmp",
        keys = { ":", "/", "?" }, -- lazy load cmp on more keys along with insert mode
        dependencies = {
          "hrsh7th/cmp-cmdline", -- add cmp-cmdline as dependency of cmp
        },
        config = function(plugin, opts)
          local cmp = require "cmp"
          -- run cmp setup
          cmp.setup(opts)

          -- configure `cmp-cmdline` as described in their repo: https://github.com/hrsh7th/cmp-cmdline#setup
          cmp.setup.cmdline("/", {
            mapping = cmp.mapping.preset.cmdline(),
            sources = {
              { name = "buffer" },
            },
          })
          cmp.setup.cmdline(":", {
            mapping = cmp.mapping.preset.cmdline(),
            sources = cmp.config.sources({
              { name = "path" },
            }, {
              {
                name = "cmdline",
                option = {
                  ignore_cmds = { "Man", "!" },
                },
              },
            }),
          })
        end,
      },
    },
  },
}