prettier/docs/options.md

id	title
options	Options

Prettier ships with a handful of customizable format options, usable in both the CLI and API.

Print Width

Specify the line length that the printer will wrap on.

For readability we recommend against using more than 80 characters:

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.

Default	CLI Override	API Override
80	--print-width <int>	printWidth: <int>

Tab Width

Specify the number of spaces per indentation-level.

Default	CLI Override	API Override
2	--tab-width <int>	tabWidth: <int>

Tabs

Indent lines with tabs instead of spaces

Default	CLI Override	API Override
false	--use-tabs	useTabs: <bool>

Semicolons

Print semicolons at the ends of statements.

Valid options:

• true - Add a semicolon at the end of every statement.
• false - Only add semicolons at the beginning of lines that may introduce ASI failures.

Default	CLI Override	API Override
true	--no-semi	semi: <bool>

Quotes

Use single quotes instead of double quotes.

Notes:

• Quotes in JSX will always be double and ignore this setting.
• 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'.

Default	CLI Override	API Override
false	--single-quote	singleQuote: <bool>

Trailing Commas

Print trailing commas wherever possible when multi-line. (A single-line array, for example, never gets trailing commas.)

Valid options:

• "none" - No trailing commas.
• "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.

Default	CLI Override	API Override
"none"	--trailing-comma <none|es5|all>	trailingComma: "<none|es5|all>"

Bracket Spacing

Print spaces between brackets in object literals.

Valid options:

• true - Example: { foo: bar }.
• false - Example: {foo: bar}.

Default	CLI Override	API Override
true	--no-bracket-spacing	bracketSpacing: <bool>

JSX Brackets

Put the > of a multi-line JSX element at the end of the last line instead of being alone on the next line (does not apply to self closing elements).

Default	CLI Override	API Override
false	--jsx-bracket-same-line	jsxBracketSameLine: <bool>

Range

Format only a segment of a file.

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:

• Backwards to the start of the first line containing the selected statement.
• Forwards to the end of the selected statement.

These options cannot be used with cursorOffset.

Default	CLI Override	API Override
0	--range-start <int>	rangeStart: <int>
Infinity	--range-end <int>	rangeEnd: <int>

Parser

Specify which parser to use.

Both the babylon and flow parsers support the same set of JavaScript features (including Flow). Prettier automatically infers the parser from the input file path, so you shouldn't have to change this setting.

Built-in parsers:

• babylon
• flow
• typescript Since v1.4.0
• postcss Since v1.4.0
• json Since v1.5.0
• graphql Since v1.5.0
• markdown Since v1.8.0

Custom parsers are also supported. Since v1.5.0

Default	CLI Override	API Override
babylon	--parser <string> --parser ./my-parser	parser: "<string>" parser: require("./my-parser")

FilePath

Specify the input filepath. This will be used to do parser inference.

For example, the following will use postcss parser:

cat foo | prettier --stdin-filepath foo.css

Default	CLI Override	API Override
None	--stdin-filepath <string>	filepath: "<string>"

Require pragma

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.

For example, a file with the following as its first comment will be formatted when --require-pragma is supplied:

/**
 * @prettier
 */

or

/**
 * @format
 */

Default	CLI Override	API Override
false	--require-pragma	requirePragma: <bool>

Insert Pragma

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.

Default	CLI Override	API Override
false	--insert-pragma	insertPragma: <bool>