JavaScript RegExp Carriage Return Metacharacter (\r)

What Is \r?

\r matches the carriage return (CR) character (U+000D, ASCII 13). It is half of Windows \r\n (CRLF) and the whole line ending in some legacy Mac text. Pair it with \n when you parse cross-platform files.

\r    → carriage return (U+000D)
\n    → line feed (different character)
\r\n  → Windows-style line ending (CR + LF)
\s    → any whitespace, including \r

"a\rb"           → CR between letters
/\r/.test(...)   → true when CR is present
/\r\n|\r|\n/     → any common line ending

How to Use \r

Treat carriage return as a concrete character — test for it, match CRLF as a pair, or normalize mixed endings.

1. Create or import text that may contain CR (string escape: "\r").
2. Use /\r/ with test, match, split, or replace.
3. For Windows files, match /\r\n/ as one unit when you care about the full ending.
4. When normalizing, list \r\n before \r so CRLF does not become two replacements.

Pseudocode

pattern has "\r"
read next character ch from the string

if ch.codePoint === 0x000D:   // carriage return
    accept match
else:
    fail this path

common actions:
  test(str)                    → true/false
  match(/\r\n/g)               → Windows breaks
  replace(/\r\n|\r/g, "\n")    → normalize to LF
  split(/\r\n|\r|\n/)          → lines for any style

Cheat Sheet

Keep these facts handy when working with carriage returns.

Live Preview

Run common \r operations on sample text with CR and CRLF.

text = "hello\rworld"
/\r/.test(text)
→ true

/* carriage return (U+000D) is present */

JavaScript Examples

Short, copy-ready snippets. Open DevTools Console, or use Try It Yourself for a live editor.

console.log(/\r/.test("hello\rworld")); // true
console.log(/\r/.test("hello\nworld")); // false
console.log(/\r/.test("a\r\nb"));       // true (CRLF includes CR)

true
false
true

const windowsText = "row1\r\nrow2\r\nrow3";

const breaks = windowsText.match(/\r\n/g);
console.log(breaks);                 // ["\r\n", "\r\n"]
console.log(breaks.length);          // 2
console.log(/\r\n/.test(windowsText)); // true

["\r\n", "\r\n"]
2
true

const mixed = "line1\r\nline2\rline3\nline4";

const unix = mixed.replace(/\r\n|\r/g, "\n");
console.log(JSON.stringify(unix));
// "line1\nline2\nline3\nline4"

console.log(unix.split("\n"));
// ["line1", "line2", "line3", "line4"]

"line1\nline2\nline3\nline4"
["line1", "line2", "line3", "line4"]

Performance Notes

Matching a single control character is cheap. Prefer a one-pass normalize when files may mix CRLF and CR, then use simple \n logic afterward.

Key Takeaways