feat(fmt): make printf working with colors.

fmt/printf.ts

@@ -1,5 +1,7 @@
 // Copyright 2018-2025 the Deno authors. MIT license.
 
+import { stripAnsiCode } from "./colors.ts";
+
 /**
  * {@linkcode sprintf} and {@linkcode printf} for printing formatted strings to
  * stdout.
@@ -389,6 +391,7 @@ class Printf {
                 this.state = State.PERCENT;
                 return;
               }
+
               flags.width = flags.width === -1 ? 0 : flags.width;
               flags.width *= 10;
               flags.width += val;
@@ -862,6 +865,10 @@ class Printf {
     if (this.flags.precision !== -1) {
       s = s.slice(0, this.flags.precision);
     }
+    const sac = stripAnsiCode(s);
+    if (sac.length !== s.length) {
+      this.flags.width += s.length - sac.length;
+    }
     return this.pad(s);
   }
 

fmt/printf_test.ts

@@ -8,6 +8,7 @@
 import { printf, sprintf } from "./printf.ts";
 import { assertEquals, assertThrows } from "@std/assert";
 import { assertSpyCall, spy } from "@std/testing/mock";
+import * as c from "./colors.ts";
 
 Deno.test("sprintf() handles noVerb", function () {
   assertEquals(sprintf("bla"), "bla");
@@ -169,6 +170,54 @@ Deno.test("sprintf() handles string", function () {
   assertEquals(sprintf("%s World%s", "Hello", "!"), "Hello World!");
 });
 
+Deno.test("printf() handles string with colors", () => {
+  assertEquals(sprintf("%4s", c.bold("foo")), " foo");
+  assertEquals(sprintf("%4s", c.dim("foo")), " foo");
+  assertEquals(sprintf("%4s", c.italic("foo")), " foo");
+  assertEquals(sprintf("%4s", c.underline("foo")), " foo");
+  assertEquals(sprintf("%4s", c.inverse("foo")), " foo");
+  assertEquals(sprintf("%4s", c.hidden("foo")), " foo");
+  assertEquals(sprintf("%4s", c.strikethrough("foo")), " foo");
+
+  assertEquals(sprintf("%4s", c.black("foo")), " foo");
+  assertEquals(sprintf("%4s", c.red("foo")), " foo");
+  assertEquals(sprintf("%4s", c.green("foo")), " foo");
+  assertEquals(sprintf("%4s", c.yellow("foo")), " foo");
+  assertEquals(sprintf("%4s", c.blue("foo")), " foo");
+  assertEquals(sprintf("%4s", c.magenta("foo")), " foo");
+  assertEquals(sprintf("%4s", c.cyan("foo")), " foo");
+  assertEquals(sprintf("%4s", c.white("foo")), " foo");
+  assertEquals(sprintf("%4s", c.gray("foo")), " foo");
+  assertEquals(sprintf("%4s", c.brightBlack("foo")), " foo");
+  assertEquals(sprintf("%4s", c.brightRed("foo")), " foo");
+  assertEquals(sprintf("%4s", c.brightGreen("foo")), " foo");
+  assertEquals(sprintf("%4s", c.brightYellow("foo")), " foo");
+  assertEquals(sprintf("%4s", c.brightBlue("foo")), " foo");
+  assertEquals(sprintf("%4s", c.brightMagenta("foo")), " foo");
+  assertEquals(sprintf("%4s", c.brightCyan("foo")), " foo");
+  assertEquals(sprintf("%4s", c.brightWhite("foo")), " foo");
+  assertEquals(sprintf("%4s", c.bgBlack("foo")), " foo");
+  assertEquals(sprintf("%4s", c.bgRed("foo")), " foo");
+  assertEquals(sprintf("%4s", c.bgGreen("foo")), " foo");
+  assertEquals(sprintf("%4s", c.bgYellow("foo")), " foo");
+  assertEquals(sprintf("%4s", c.bgBlue("foo")), " foo");
+  assertEquals(sprintf("%4s", c.bgMagenta("foo")), " foo");
+  assertEquals(sprintf("%4s", c.bgCyan("foo")), " foo");
+  assertEquals(sprintf("%4s", c.bgWhite("foo")), " foo");
+  assertEquals(sprintf("%4s", c.bgBrightBlack("foo")), " foo");
+  assertEquals(sprintf("%4s", c.bgBrightRed("foo")), " foo");
+  assertEquals(sprintf("%4s", c.bgBrightGreen("foo")), " foo");
+  assertEquals(sprintf("%4s", c.bgBrightYellow("foo")), " foo");
+  assertEquals(sprintf("%4s", c.bgBrightBlue("foo")), " foo");
+  assertEquals(sprintf("%4s", c.bgBrightMagenta("foo")), " foo");
+  assertEquals(sprintf("%4s", c.bgBrightCyan("foo")), " foo");
+  assertEquals(sprintf("%4s", c.bgBrightWhite("foo")), " foo");
+  assertEquals(sprintf("%4s", c.rgb8("foo", -10)), " foo");
+  assertEquals(sprintf("%4s", c.rgb8("foo", 42.5)), " foo");
+  assertEquals(sprintf("%4s", c.rgb8("foo", 42)), " foo");
+  assertEquals(sprintf("%4s", c.bgRgb8("foo", 42)), " foo");
+});
+
 Deno.test("sprintf() handles hex", function () {
   assertEquals(sprintf("%x", "123"), "313233");
   assertEquals(sprintf("%x", "n"), "6e");