Fix large file preview on telescope

.config/nvim/lua/config/telescope.lua

@@ -1,21 +1,32 @@
-local pickers = require('telescope.pickers')
-local finders = require('telescope.finders')
 local previewers = require('telescope.previewers')
-local action_state = require('telescope.actions.state')
-local conf = require('telescope.config').values
+local previewers_utils = require('telescope.previewers.utils')
 local builtin = require('telescope.builtin')
 local sorters = require('telescope.sorters')
 local actions = require('telescope.actions')
 
+local max_size = 100000
+local truncate_large_files = function(filepath, bufnr, opts)
+    opts = opts or {}
+
+    filepath = vim.fn.expand(filepath)
+    vim.loop.fs_stat(filepath, function(_, stat)
+        if not stat then return end
+        if stat.size > max_size then
+            local cmd = {"head", "-c", max_size, filepath}
+            previewers_utils.job_maker(cmd, bufnr, opts)
+        else
+            previewers.buffer_previewer_maker(filepath, bufnr, opts)
+        end
+    end)
+end
+
 require('telescope').setup({
 	defaults = {
 		file_sorter = sorters.get_fzy_sorter,
 		prompt_prefix = ' >',
 		color_devicons = true,
 
-		file_previewer = previewers.vim_buffer_cat.new,
-		grep_previewer = previewers.vim_buffer_vimgrep.new,
-		qflist_previewer = previewers.vim_buffer_qflist.new,
+        buffer_previewer_maker = truncate_large_files,
 
         initial_mode = "insert",
         selection_strategy = "reset",