feat: filter diagnostics by severity level (#285)

* feat: filter diagnostics by severity level, with default keybind `s`

* update doc

* remove level printing

* change severity type to lsp.DiagnosticSeverity

* update README

README.md

@@ -61,6 +61,7 @@ Trouble comes with the following defaults:
     width = 50, -- width of the list when position is left or right
     icons = true, -- use devicons for filenames
     mode = "workspace_diagnostics", -- "workspace_diagnostics", "document_diagnostics", "quickfix", "lsp_references", "loclist"
+    severity = nil, -- nil (ALL) or vim.diagnostic.severity.ERROR | WARN | INFO | HINT
     fold_open = "", -- icon used for open folds
     fold_closed = "", -- icon used for closed folds
     group = true, -- group results by file
@@ -77,6 +78,7 @@ Trouble comes with the following defaults:
         open_tab = { "<c-t>" }, -- open buffer in new tab
         jump_close = {"o"}, -- jump to the diagnostic and close the list
         toggle_mode = "m", -- toggle between "workspace" and "document" diagnostics mode
+        switch_severity = "s", -- switch "diagnostics" severity filter level to HINT / INFO / WARN / ERROR
         toggle_preview = "P", -- toggle auto_preview
         hover = "K", -- opens a small popup with the full multiline message
         preview = "p", -- preview the diagnostic location

lua/trouble/config.lua

@@ -5,6 +5,7 @@ M.namespace = vim.api.nvim_create_namespace("Trouble")
 ---@class TroubleOptions
 ---@field buf number|nil
 ---@field win number|nil
+---@field severity lsp.DiagnosticSeverity|nil
 -- TODO: make some options configurable per mode
 -- TODO: make it possible to have multiple trouble lists open at the same time
 local defaults = {
@@ -17,6 +18,7 @@ local defaults = {
   width = 50, -- width of the list when position is left or right
   icons = true, -- use devicons for filenames
   mode = "workspace_diagnostics", -- "workspace_diagnostics", "document_diagnostics", "quickfix", "lsp_references", "loclist"
+  severity = nil, -- nil (ALL) or vim.diagnostic.severity.ERROR | WARN | INFO | HINT
   fold_open = "", -- icon used for open folds
   fold_closed = "", -- icon used for closed folds
   action_keys = { -- key mappings for actions in the trouble list
@@ -29,6 +31,7 @@ local defaults = {
     open_tab = { "<c-t>" }, -- open buffer in new tab
     jump_close = { "o" }, -- jump to the diagnostic and close the list
     toggle_mode = "m", -- toggle between "workspace" and "document" mode
+    switch_severity = "s", -- switch "diagnostics" severity filter level to ALL / HINT / INFO / WARN / ERROR
     toggle_preview = "P", -- toggle auto_preview
     hover = "K", -- opens a small popup with the full multiline message
     preview = "p", -- preview the diagnostic location

lua/trouble/init.lua

@@ -60,6 +60,11 @@ function Trouble.open(...)
   if opts.mode and (opts.mode ~= config.options.mode) then
     config.options.mode = opts.mode
   end
+
+  if opts.severity and (opts.severity ~=config.options.severity) then
+    config.options.severity = opts.severity
+  end
+
   opts.focus = true
   opts.on_open = true
 
@@ -169,6 +174,17 @@ function Trouble.action(action)
     action = "refresh"
   end
 
+  if action == 'switch_severity' then
+    if config.options.severity == nil then
+      config.options.severity = vim.diagnostic.severity.ERROR
+    elseif config.options.severity < 4 then
+      config.options.severity = config.options.severity + 1
+    else
+      config.options.severity = nil
+    end
+    action = "refresh"
+  end
+
   if view and action == "on_win_enter" then
     view:on_win_enter()
   end

lua/trouble/providers/diagnostic.lua

@@ -13,7 +13,7 @@ function M.diagnostics(_, buf, cb, options)
   local items = {}
 
   if vim.diagnostic then
-    local diags = vim.diagnostic.get(buf)
+    local diags = vim.diagnostic.get(buf, { severity = options.severity })
     for _, item in ipairs(diags) do
       table.insert(items, util.process_item(item))
     end