add nvim-ufo for folding

after/ftplugin/json.vim

@@ -1,6 +1,2 @@
 " let the initial folding state be that all folds are closed.
-set foldlevel=0
-
-" Use nvim-treesitter for folding
-set foldmethod=expr
-set foldexpr=nvim_treesitter#foldexpr()
+setlocal foldlevel=0

lua/config/ufo.lua

@@ -0,0 +1,14 @@
+ -- disable foldcolumn, see https://github.com/kevinhwang91/nvim-ufo/issues/4
+vim.o.foldcolumn = '0'
+vim.o.foldlevel = 99 -- Using ufo provider need a large value, feel free to decrease the value
+vim.o.foldlevelstart = 99
+vim.o.foldenable = true
+
+-- treesitter as a main provider instead
+-- Only depend on `nvim-treesitter/queries/filetype/folds.scm`,
+-- performance and stability are better than `foldmethod=nvim_treesitter#foldexpr()`
+require('ufo').setup({
+    provider_selector = function(bufnr, filetype, buftype)
+        return {'treesitter', 'indent'}
+    end
+})

lua/plugin_specs.lua

@@ -50,7 +50,7 @@ local plugin_specs = {
   {
     "nvim-treesitter/nvim-treesitter",
     enabled = function()
-      if vim.g.is_mac then
+      if vim.g.is_mac or vim.g.is_linux then
         return true
       end
       return false
@@ -488,6 +488,14 @@ local plugin_specs = {
       require("config.fidget-nvim")
     end,
   },
+  {
+    'kevinhwang91/nvim-ufo',
+    dependencies = {'kevinhwang91/promise-async'},
+    event = { "VeryLazy" },
+    config = function()
+      require("config.ufo")
+    end
+  }
 }
 
 -- configuration for lazy itself.