feat(picker.finder): optional transform function

lua/snacks/picker/config/defaults.lua

@@ -73,6 +73,7 @@ local M = {}
 ---@field preview? snacks.picker.preview|string preview function or preset
 ---@field matcher? snacks.picker.matcher.Config matcher config
 ---@field sort? snacks.picker.sort|snacks.picker.sort.Config sort function or config
+---@field transform? string|snacks.picker.transform transform/filter function
 --- UI
 ---@field win? snacks.picker.win.Config
 ---@field layout? snacks.picker.layout.Config|string|{}|fun(source:string):(snacks.picker.layout.Config|string)

lua/snacks/picker/core/finder.lua

@@ -12,6 +12,7 @@ M.__index = M
 ---@field picker snacks.Picker
 ---@field filter snacks.picker.Filter
 ---@field async snacks.picker.Async
+---@field meta table<string, any>
 
 ---@alias snacks.picker.finder.async fun(cb:async fun(item:snacks.picker.finder.Item))
 ---@alias snacks.picker.finder.result snacks.picker.finder.Item[] | snacks.picker.finder.async
@@ -64,6 +65,7 @@ function M:ctx(picker)
       end,
     }),
     filter = self.filter,
+    meta = {},
   }
   setmetatable(ret, { __index = M:deprecated(self.filter) })
   return ret
@@ -119,6 +121,19 @@ function M:run(picker)
     self.items[item.idx] = item
   end
 
+  if picker.opts.transform then
+    local transform = Snacks.picker.config.transform(picker.opts)
+    ---@param item snacks.picker.finder.Item
+    function add(item)
+      local t = transform(item, ctx)
+      item = type(t) == "table" and t or item
+      if t ~= false then
+        item.idx, item.score = #self.items + 1, default_score
+        self.items[item.idx] = item
+      end
+    end
+  end
+
   -- PERF: if finder is a table, we can skip the async part
   if type(finder) == "table" then
     local items = finder --[[@as snacks.picker.finder.Item[] ]]

lua/snacks/picker/transform.lua

@@ -0,0 +1,18 @@
+---@class snacks.picker.transformers
+---@field [string] snacks.picker.transform
+local M = {}
+
+function M.unique_file(item, ctx)
+  ctx.meta.done = ctx.meta.done or {} ---@type table<string, boolean>
+  local path = Snacks.picker.util.path(item)
+  if not path or ctx.meta.done[path] then
+    return false
+  end
+  ctx.meta.done[path] = true
+end
+
+function M.text_to_file(item, ctx)
+  item.file = item.file or item.text
+end
+
+return M