detect-newline

Detect and normalize line endings — \n (LF), \r\n (CRLF), and \r (CR). Zero dependencies and no_std. A Rust take on Node's detect-newline, plus the conversion and line-splitting you usually reach for next.

use detect_newline::{detect, dominant, to_lf, lines, Newline};

assert_eq!(detect("a\r\nb"), Some(Newline::CrLf));        // first ending found
assert_eq!(dominant("a\nb\nc\r\nd"), Some(Newline::Lf));  // most common
assert_eq!(to_lf("a\r\nb\rc"), "a\nb\nc");                // normalize
assert_eq!(lines("a\r\nb\rc").collect::<Vec<_>>(), ["a", "b", "c"]); // CR-aware

Why detect-newline?

The Rust standard library's str::lines splits on \n/\r\n but not a lone \r, and there's no built-in way to detect a string's line-ending style or normalize a mixed string to one. This crate is the small, focused piece — pick a window of text apart by line ending, decide which one a file uses, and convert between them.

[dependencies]
detect-newline = "0.1"

API

Item	Purpose
`detect(text)`	The first line ending, or `None`
`dominant(text)`	The most frequent line ending (ties → first occurrence)
`count(text)`	`Counts { lf, crlf, cr }` of each style
`normalize(text, to)` / `to_lf` / `to_crlf` / `to_cr`	Convert every ending to one style
`lines(text)`	Iterate lines, splitting on `\n`, `\r\n`, and lone `\r`
`has_trailing_newline(text)` / `strip_trailing_newline(text)`	Trailing-ending helpers
`Newline`	`Lf` (default), `CrLf`, `Cr`

Behavior

\r\n is always one line ending, never a \r followed by a \n — in detection, counting, normalization, and splitting alike.
detect returns the first ending found; dominant returns the most frequent, breaking ties toward whichever style occurs first.
normalize operates on character boundaries (safe for any UTF-8) and is idempotent.
lines mirrors str::lines but also splits a lone \r; a single trailing line ending does not yield a final empty line.

`no_std`

#![no_std] (needs only alloc for String) with zero dependencies.

Contributors ✨

This project follows the all-contributors specification. Contributions of any kind are welcome — code, docs, bug reports, ideas, reviews! See the emoji key for how each contribution is recognized, and open a PR or issue to get involved.

Thanks goes to these wonderful people:

License

Licensed under either of Apache-2.0 or MIT at your option.

detect-newline 0.1.1