What is stylelint?
Stylelint is a powerful, modern linter that helps you avoid errors and enforce consistent conventions in your stylesheets. It is configurable and supports the latest CSS syntax as well as CSS-like syntaxes, such as SCSS.
What are stylelint's main functionalities?
Linting CSS files
This command will lint all CSS files in the 'src' directory and its subdirectories. It will check for errors and code quality issues based on the rules defined in the configuration.
"stylelint 'src/**/*.css'"
Fixing CSS files
This command will not only lint the CSS files but also attempt to fix any fixable issues, such as formatting inconsistencies, automatically.
"stylelint 'src/**/*.css' --fix"
Custom configuration
This JSON represents a custom Stylelint configuration object where specific rules are defined, such as disallowing invalid hex colors, setting indentation preferences, and enforcing no leading zero for numbers.
{ "rules": { "color-no-invalid-hex": true, "indentation": [2, { "except": ["block"] }], "number-leading-zero": "never" } }
Extending configurations
This JSON represents a Stylelint configuration that extends a shared configuration, in this case, 'stylelint-config-standard', which is a popular set of rules that enforce common stylistic conventions.
{ "extends": "stylelint-config-standard" }
Using plugins
This JSON represents a Stylelint configuration that includes a plugin, 'stylelint-scss', which adds SCSS-specific linting rules to Stylelint. The configuration then enables a rule from that plugin to disallow unknown at-rules in SCSS.
{ "plugins": ["stylelint-scss"], "rules": { "scss/at-rule-no-unknown": true } }
Other packages similar to stylelint
eslint
ESLint is a static code analysis tool for identifying problematic patterns in JavaScript code. It is similar to Stylelint in its extensibility and plugin ecosystem but is focused on JavaScript rather than stylesheets.
prettier
Prettier is an opinionated code formatter that supports many languages, including CSS. Unlike Stylelint, which can both lint and fix code, Prettier is solely focused on code formatting and does not provide linting functionalities.
sass-lint
Sass-lint is a node-only Sass linter for both sass and scss syntax. It is similar to Stylelint when working with SCSS files but does not support plain CSS or other CSS-like syntaxes.
csslint
CSSLint is a tool that helps to point out problems with your CSS code. It is less configurable than Stylelint and has a smaller set of rules and plugins, but it serves a similar purpose in linting CSS files.
unit-case
Specify lowercase or uppercase for units.
a { width: 10px; }
Options
string
: "lower"|"upper"
"lower"
The following patterns are considered warnings:
a {
width: 10PX;
}
a {
width: 10Px;
}
a {
width: 10pX;
}
a {
width: 10PIXEL;
}
a {
width: calc(10PX * 2);
}
The following patterns are not considered warnings:
a {
width: 10px;
}
a {
width: calc(10px * 2);
}
"upper"
The following patterns are considered warnings:
a {
width: 10px;
}
a {
width: 10Px;
}
a {
width: 10pX;
}
a {
width: 10pixel;
}
a {
width: calc(10px * 2);
}
The following patterns are not considered warnings:
a {
width: 10PX;
}
a {
width: calc(10PX * 2);
}