prettier

Prettier is the industry-leading opinionated code formatter that brings consistency to JavaScript and many other languages by automatically reformatting code according to proven formatting principles. It eliminates formatting debates and ensures uniform code style across entire development teams.

Key Features:

Multi-Language Support: Formats JavaScript, TypeScript, CSS, HTML, JSON, Markdown, YAML, and 20+ other languages
Opinionated Formatting: Zero-configuration approach with sensible defaults that work well for most projects
Parse Safety: Ensures formatted code maintains semantic equivalence to the original through AST-based processing
Consistent Output: Deterministic formatting produces identical results regardless of environment or developer
Team Standardization: Eliminates style discussions and ensures consistent formatting across team members
Fast Performance: High-speed formatting suitable for large codebases
Configuration Flexibility: Supports project-specific settings through .prettierrc files when customization is needed
Git Integration: Reduces merge conflicts by maintaining consistent formatting across branches

prettier documentation

Version in MegaLinter: 3.6.2
Visit Official Web Site
See How to configure prettier rules
See How to disable prettier rules in files
See Index of problems detected by prettier

Configuration in MegaLinter

Enable prettier by adding JAVASCRIPT_PRETTIER in ENABLE_LINTERS variable
Disable prettier by adding JAVASCRIPT_PRETTIER in DISABLE_LINTERS variable

Enable autofixes by adding JAVASCRIPT_PRETTIER in APPLY_FIXES variable

Variable	Description	Default value
JAVASCRIPT_DEFAULT_STYLE	For prettier to be active, JAVASCRIPT_DEFAULT_STYLE must be `prettier`	`standard`
JAVASCRIPT_PRETTIER_ARGUMENTS	User custom arguments to add in linter CLI call Ex: `-s --foo "bar"`
JAVASCRIPT_PRETTIER_COMMAND_REMOVE_ARGUMENTS	User custom arguments to remove from command line before calling the linter Ex: `-s --foo "bar"`
JAVASCRIPT_PRETTIER_FILTER_REGEX_INCLUDE	Custom regex including filter Ex: `(src\\|lib)`	Include every file
JAVASCRIPT_PRETTIER_FILTER_REGEX_EXCLUDE	Custom regex excluding filter Ex: `(test\\|examples)`	Exclude no file
JAVASCRIPT_PRETTIER_CLI_LINT_MODE	Override default CLI lint mode - `file`: Calls the linter for each file - `list_of_files`: Call the linter with the list of files as argument - `project`: Call the linter from the root of the project	`list_of_files`
JAVASCRIPT_PRETTIER_FILE_EXTENSIONS	Allowed file extensions. `"*"` matches any extension, `""` matches empty extension. Empty list excludes all files Ex: `[".py", ""]`	`[".js"]`
JAVASCRIPT_PRETTIER_FILE_NAMES_REGEX	File name regex filters. Regular expression list for filtering files by their base names using regex full match. Empty list includes all files Ex: `["Dockerfile(-.+)?", "Jenkinsfile"]`	Include every file
JAVASCRIPT_PRETTIER_PRE_COMMANDS	List of bash commands to run before the linter	None
JAVASCRIPT_PRETTIER_POST_COMMANDS	List of bash commands to run after the linter	None
JAVASCRIPT_PRETTIER_UNSECURED_ENV_VARIABLES	List of env variables explicitly not filtered before calling JAVASCRIPT_PRETTIER and its pre/post commands	None
JAVASCRIPT_PRETTIER_CONFIG_FILE	prettier configuration file nameUse `LINTER_DEFAULT` to let the linter find it	`.prettierrc.json`
JAVASCRIPT_PRETTIER_RULES_PATH	Path where to find linter configuration file	Workspace folder, then MegaLinter default rules
JAVASCRIPT_PRETTIER_DISABLE_ERRORS	Run linter but consider errors as warnings	`true`
JAVASCRIPT_PRETTIER_DISABLE_ERRORS_IF_LESS_THAN	Maximum number of errors allowed	`0`
JAVASCRIPT_PRETTIER_CLI_EXECUTABLE	Override CLI executable	`['prettier']`

IDE Integration

Use prettier in your favorite IDE to catch errors before MegaLinter !

IDE	Extension Name	Install
Emacs	prettier-emacs	Visit Web Site
Emacs	prettier.el	Visit Web Site
Emacs	apheleia	Visit Web Site
IDEA	Prettier
Sublime Text	JsPrettier	Visit Web Site
vim	vim-prettier	Visit Web Site
visual_studio	JavaScriptPrettier	Visit Web Site
Visual Studio Code	prettier-vscode

MegaLinter Flavors

This linter is available in the following flavors

Flavor	Description	Embedded linters
all	Default MegaLinter Flavor	127
cupcake	MegaLinter for the most commonly used languages	88
dotnetweb	Optimized for C, C++, C# or VB based projects with JS/TS	74
formatters	Contains only formatters	18
javascript	Optimized for JAVASCRIPT or TYPESCRIPT based projects	60

Behind the scenes

How are identified applicable files

File extensions: .js

How the linting is performed

prettier is called once with the list of files as arguments (list_of_files CLI lint mode)

Example calls

prettier --check myfile.js

prettier --config .prettierrc.json --check myfile.js

prettier --config .prettierrc.json --write myfile.js

Help content

Usage: prettier [options] [file/dir/glob ...]

By default, output is written to stdout.
Stdin is read if it is piped to Prettier and no files are given.

Output options:

  -c, --check              Check if the given files are formatted, print a human-friendly summary
                           message and paths to unformatted files (see also --list-different).
  -l, --list-different     Print the names of files that are different from Prettier's formatting (see also --check).
  -w, --write              Edit files in-place. (Beware!)

Format options:

  --arrow-parens <always|avoid>
                           Include parentheses around a sole arrow function parameter.
                           Defaults to always.
  --bracket-same-line      Put > of opening tags on the last line instead of on a new line.
                           Defaults to false.
  --no-bracket-spacing     Do not print spaces between brackets.
  --embedded-language-formatting <auto|off>
                           Control how Prettier formats quoted code embedded in the file.
                           Defaults to auto.
  --end-of-line <lf|crlf|cr|auto>
                           Which end of line characters to apply.
                           Defaults to lf.
  --experimental-operator-position <start|end>
                           Where to print operators when binary expressions wrap lines.
                           Defaults to end.
  --no-experimental-ternaries
                           Default behavior of ternaries; keep question marks on the same line as the consequent.
  --html-whitespace-sensitivity <css|strict|ignore>
                           How to handle whitespaces in HTML.
                           Defaults to css.
  --jsx-single-quote       Use single quotes in JSX.
                           Defaults to false.
  --object-wrap <preserve|collapse>
                           How to wrap object literals.
                           Defaults to preserve.
  --parser <flow|babel|babel-flow|babel-ts|typescript|acorn|espree|meriyah|css|less|scss|json|json5|jsonc|json-stringify|graphql|markdown|mdx|vue|yaml|glimmer|html|angular|lwc|mjml>
                           Which parser to use.
  --print-width <int>      The line length where Prettier will try wrap.
                           Defaults to 80.
  --prose-wrap <always|never|preserve>
                           How to wrap prose.
                           Defaults to preserve.
  --quote-props <as-needed|consistent|preserve>
                           Change when properties in objects are quoted.
                           Defaults to as-needed.
  --no-semi                Do not print semicolons, except at the beginning of lines which may need them.
  --single-attribute-per-line
                           Enforce single attribute per line in HTML, Vue and JSX.
                           Defaults to false.
  --single-quote           Use single quotes instead of double quotes.
                           Defaults to false.
  --tab-width <int>        Number of spaces per indentation level.
                           Defaults to 2.
  --trailing-comma <all|es5|none>
                           Print trailing commas wherever possible when multi-line.
                           Defaults to all.
  --use-tabs               Indent with tabs instead of spaces.
                           Defaults to false.
  --vue-indent-script-and-style
                           Indent script and style tags in Vue files.
                           Defaults to false.

Config options:

  --config <path>          Path to a Prettier configuration file (.prettierrc, package.json, prettier.config.js).
  --no-config              Do not look for a configuration file.
  --config-precedence <cli-override|file-override|prefer-file>
                           Define in which order config files and CLI options should be evaluated.
                           Defaults to cli-override.
  --no-editorconfig        Don't take .editorconfig into account when parsing configuration.
  --find-config-path <path>
                           Find and print the path to a configuration file for the given input file.
  --ignore-path <path>     Path to a file with patterns describing files to ignore.
                           Multiple values are accepted.
                           Defaults to [.gitignore, .prettierignore].
  --plugin <path>          Add a plugin. Multiple plugins can be passed as separate `--plugin`s.
                           Defaults to [].
  --with-node-modules      Process files inside 'node_modules' directory.

Editor options:

  --cursor-offset <int>    Print (to stderr) where a cursor at the given position would move to after formatting.
                           Defaults to -1.
  --range-end <int>        Format code ending at a given character offset (exclusive).
                           The range will extend forwards to the end of the selected statement.
                           Defaults to Infinity.
  --range-start <int>      Format code starting at a given character offset.
                           The range will extend backwards to the start of the first line containing the selected statement.
                           Defaults to 0.

Other options:

  --cache                  Only format changed files. Cannot use with --stdin-filepath.
                           Defaults to false.
  --cache-location <path>  Path to the cache file.
  --cache-strategy <metadata|content>
                           Strategy for the cache to use for detecting changed files.
  --check-ignore-pragma    Check whether the file's first docblock comment contains '@noprettier' or '@noformat' to determine if it should be formatted.
                           Defaults to false.
  --no-color               Do not colorize error messages.
  --no-error-on-unmatched-pattern
                           Prevent errors when pattern is unmatched.
  --file-info <path>       Extract the following info (as JSON) for a given file path. Reported fields:
                           * ignored (boolean) - true if file path is filtered by --ignore-path
                           * inferredParser (string | null) - name of parser inferred from file path
  -h, --help <flag>        Show CLI usage, or details about the given flag.
                           Example: --help write
  -u, --ignore-unknown     Ignore unknown files.
  --insert-pragma          Insert @format pragma into file's first docblock comment.
                           Defaults to false.
  --log-level <silent|error|warn|log|debug>
                           What level of logs to report.
                           Defaults to log.
  --require-pragma         Require either '@prettier' or '@format' to be present in the file's first docblock comment in order for it to be formatted.
                           Defaults to false.
  --stdin-filepath <path>  Path to the file to pretend that stdin comes from.
  --support-info           Print support information as JSON.
  -v, --version            Print Prettier version.

Installation on mega-linter Docker image

Dockerfile commands :

# renovate: datasource=npm depName=prettier
ARG NPM_PRETTIER_VERSION=3.6.2

NPM packages (node.js):
- prettier@3.6.2