feat(utils): add function to strip ansi sequences

spec/00-utils_spec.lua

@@ -206,4 +206,61 @@ describe("Utils", function()
 
   end)
 
+
+
+  describe("strip_ansi()", function()
+
+    it("returns empty string unchanged", function()
+      assert.are.equal("", utils.strip_ansi(""))
+    end)
+
+
+    it("errors on nil", function()
+      assert.has_error(function()
+        utils.strip_ansi(nil)
+      end)
+    end)
+
+
+    it("returns plain text unchanged", function()
+      assert.are.equal("plain", utils.strip_ansi("plain"))
+      assert.are.equal("hello world", utils.strip_ansi("hello world"))
+    end)
+
+
+    it("strips SGR (color/attribute) sequences", function()
+      local red = "\27[31m"
+      local reset = "\27[0m"
+      assert.are.equal("red", utils.strip_ansi(red .. "red" .. reset))
+      assert.are.equal("bold", utils.strip_ansi("\27[1mbold\27[0m"))
+    end)
+
+
+    it("strips CSI cursor/control sequences", function()
+      assert.are.equal("", utils.strip_ansi("\27[2J\27[H"))
+      assert.are.equal("x", utils.strip_ansi("\27[10;20Hx\27[6n"))
+      assert.are.equal("ab", utils.strip_ansi("a\27[1Kb"))
+    end)
+
+
+    it("strips OSC sequences (until BEL or ST)", function()
+      assert.are.equal("", utils.strip_ansi("\27]0;title\7"))
+      assert.are.equal("xy", utils.strip_ansi("x\27]1;http://example.com\27\\y"))
+      assert.are.equal("y", utils.strip_ansi("\27]1;url\27\\y"))
+    end)
+
+
+    it("strips C1 CSI (0x9b)", function()
+      -- 0x9b is C1 CSI (same as ESC [); following bytes are params + final, e.g. "31m"
+      assert.are.equal("x", utils.strip_ansi("\15531mx"))
+    end)
+
+
+    it("strips mixed content", function()
+      local s = "\27[1m\27[31mbold red\27[0m and \27[32mgreen\27[0m"
+      assert.are.equal("bold red and green", utils.strip_ansi(s))
+    end)
+
+  end)
+
 end)

src/terminal/utils.lua

@@ -357,6 +357,25 @@ end
 
 
 
+--- Strips all ANSI escape sequences from a string.
+-- Removes CSI (e.g. colors, cursor movement, SGR), OSC, DCS, SOS, PM, APC,
+-- two-byte sequences, and C1 control codes. Use when you need plain text
+-- without terminal control sequences.
+-- @tparam string str The string that may contain ANSI sequences.
+-- @treturn string The string with all ANSI sequences removed.
+-- @usage
+-- strip_ansi("\27[31mred\27[0m")  -- "red"
+-- @within Text
+function M.strip_ansi(str)
+  return str               -- Note: order is important here
+    :gsub("\27%].-\7", "")                -- OSC (terminated by BEL)
+    :gsub("\27%].-\27%\\", "")            -- OSC (terminated by ST)
+    :gsub("\27[P^X_].-\27%\\", "")        -- DCS, SOS, PM, APC
+    :gsub("\27%[[0-?]*[ -/]*[@-~]", "")   -- CSI
+    :gsub("\155[0-?]*[ -/]*[@-~]", "")    -- C1 CSI
+    :gsub("\27[@-_]", "")                 -- two-byte sequences
+end
+
 
 
 --- Truncates text to fit within a given width, adding ellipsis as needed.