> In code styleguides, maximum line length rules are often set to 100 or 120. However, when humans write code, they don't strive to reach the maximum number of columns on every line. Developers often use whitespace to break up long lines for readability. In practice, the average line length often ends up well below the maximum.
> Prettier, on the other hand, strives to fit the most code into every line. With the print width set to 120, prettier may produce overly compact, or otherwise undesirable code.
- If the number of quotes outweighs the other quote, the quote which is less used will be used to format the string - Example: `"I'm double quoted"` results in `"I'm double quoted"` and `"This \"example\" is single quoted"` results in `'This "example" is single quoted'`.
-`"es5"` - Trailing commas where valid in ES5 (objects, arrays, etc.)
-`"all"` - Trailing commas wherever possible (including function arguments). This requires node 8 or a [transform](https://babeljs.io/docs/plugins/syntax-trailing-function-commas/).
These two options can be used to format code starting and ending at a given character offset (inclusive and exclusive, respectively). The range will extend:
Both the `babylon` and `flow` parsers support the same set of JavaScript features (including Flow type annotations). They might differ in some edge cases, so if you run into one of those you can try `flow` instead of `babylon`.
-`"css"` (via [postcss-scss](https://github.com/postcss/postcss-scss) and [postcss-less](https://github.com/shellscape/postcss-less), autodetects which to use) _Since v1.7.1_
-`"scss"` (same parsers as `"css"`, prefers postcss-scss) _Since v1.7.1_
-`"less"` (same parsers as `"css"`, prefers postcss-less) _Since v1.7.1_
-`"vue"` (same parser as `"html"`, but also formats vue-specific syntax) _Since 1.10.0_
-`"angular"` (same parser as `"html"`, but also formats angular-specific syntax via [angular-estree-parser](https://github.com/ikatyang/angular-estree-parser)) _Since 1.15.0_
Prettier can restrict itself to only format files that contain a special comment, called a pragma, at the top of the file. This is very useful when gradually transitioning large, unformatted codebases to prettier.
Prettier can insert a special @format marker at the top of files specifying that the file has been formatted with prettier. This works well when used in tandem with the `--require-pragma` option. If there is already a docblock at the top of the file then this option will add a newline to it with the @format marker.
By default, Prettier will wrap markdown text as-is since some services use a linebreak-sensitive renderer, e.g. GitHub comment and BitBucket. In some cases you may want to rely on editor/viewer soft wrapping instead, so this option allows you to opt out with `"never"`.
For historical reasons, there exist two commonly used flavors of line endings in text files. That is `\n` (or `LF` for _Line Feed_) and `\r\n` (or `CRLF` for _Carriage Return + Line Feed_).
The former is common on Linux and macOS, while the latter is prevalent on Windows.
Some details explaining why it is so [can be found on Wikipedia](https://en.wikipedia.org/wiki/Newline).
By default, Prettier preserves a flavor of line endings a given file has already used.
It also converts mixed line endings within one file to what it finds at the end of the first line.
When people collaborate on a project from different operating systems, it becomes easy to end up with mixed line endings in the central git repository.
It is also possible for Windows users to accidentally change line endings in an already committed file from `LF` to `CRLF`.
Doing so produces a large `git diff`, and if it get unnoticed during code review, all line-by-line history for the file (`git blame`) gets lost.
If you want to make sure that your git repository only contains Linux-style line endings in files covered by Prettier:
1. Set `endOfLine` option to `lf`
1. Configure [a pre-commit hook](./precommit.md) that will run Prettier
1. Configure Prettier to run in your CI pipeline (e.g. using [`prettier-check` npm package](https://www.npmjs.com/package/prettier-check))
1. Ask Windows users to run `git config core.autocrlf false` before working on your repo so that git did not convert `LF` to `CRLF` on checkout.
Alternatively, you can add `* text=auto eol=lf` to the repo's `.gitattributes` file to achieve this.
All modern text editors in all operating systems are able to correctly display line endings when `\n` (`LF`) is used.
However, old versions of Notepad for Windows will visually squash such lines into one.
Valid options:
-`"auto"` - Maintain existing line endings
(mixed values within one file are normalised by looking at what's used after the first line)
-`"lf"`– Line Feed only (`\n`), common on Linux and macOS as well as inside git repos
-`"crlf"` - Carriage Return + Line Feed characters (`\r\n`), common on Windows
-`"cr"` - Carriage Return character only (`\r`), used very rarely