id: options
Prettier ships with a handful of customizable format options, usable in both the CLI and API.
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> |
(If you don't want line wrapping when formatting Markdown, you can set the Prose Wrap option to disable it.)
Specify the number of spaces per indentation-level.
Default | CLI Override | API Override |
---|---|---|
2 |
--tab-width <int> |
tabWidth: <int> |
Indent lines with tabs instead of spaces
Default | CLI Override | API Override |
---|---|---|
false |
--use-tabs |
useTabs: <bool> |
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> |
Use single quotes instead of double quotes.
Notes:
"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> |
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 |
trailingComma: "" |
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> |
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).
Valid options:
true
- Example:<button
className="prettier-class"
id="prettier-id"
onClick={this.handleClick}>
Click Here
</button>
false
- Example:<button
className="prettier-class"
id="prettier-id"
onClick={this.handleClick}
>
Click Here
</button>
Default | CLI Override | API Override |
---|---|---|
false |
--jsx-bracket-same-line |
jsxBracketSameLine: <bool> |
available in v1.9.0+
Include parentheses around a sole arrow function parameter.
Valid options:
"avoid"
- Omit parens when possible. Example: x => x
"always"
- Always include parens. Example: (x) => x
Default | CLI Override | API Override |
---|---|---|
"avoid" |
--arrow-parens |
arrowParens: "" |
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:
These options cannot be used with cursorOffset
.
Default | CLI Override | API Override |
---|---|---|
0 |
--range-start <int> |
rangeStart: <int> |
Infinity |
--range-end <int> |
rangeEnd: <int> |
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 v1.4.0postcss
Since v1.4.0json
Since v1.5.0graphql
Since v1.5.0markdown
Since v1.8.0Custom parsers are also supported. Since v1.5.0
Default | CLI Override | API Override |
---|---|---|
None | --parser <string> --parser ./my-parser |
parser: "<string>" parser: require("./my-parser") |
Note: the default value was "babylon"
until v1.13.0.
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>" |
available in v1.7.0+
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.
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> |
available in v1.8.0+
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> |
available in v1.8.2+
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"
.
Valid options:
"always"
- Wrap prose if it exceeds the print width."never"
- Do not wrap prose."preserve"
- Wrap prose as-is. available in v1.9.0+Default | CLI Override | API Override |
---|---|---|
"preserve" |
--prose-wrap |
proseWrap: "" |