noUnknownFunction (CSS)
Language CSS
Summary
Section titled “Summary”- Rule available since:
v1.8.0 - Diagnostic Category:
lint/correctness/noUnknownFunction - This rule is recommended, meaning it is enabled by default.
- This rule doesn’t have a fix.
- The default severity of this rule is error.
- Sources:
- Same as
function-no-unknown
- Same as
How to configure
Section titled “How to configure”{ "linter": { "rules": { "correctness": { "noUnknownFunction": "error" } } }}Description
Section titled “Description”Disallow unrecognized CSS value functions.
This rule ignores double-dashed custom functions, e.g. --custom-function().
In SCSS files, it also ignores SCSS built-in functions and functions declared in the same file.
SCSS limitations
Section titled “SCSS limitations”The rule does not resolve functions made globally available by legacy SCSS @import.
Configure the ignore option for imported functions that cannot be resolved locally.
Data sources of known CSS value functions are:
- MDN reference on CSS value functions
- MDN reference on CSS reference
- MDN browser compatibility data for CSS value functions
Examples
Section titled “Examples”Invalid
Section titled “Invalid”a { transform: unknown(1); }code-block.css:1:16 lint/correctness/noUnknownFunction ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
✖ Unexpected unknown function: unknown
> 1 │ a { transform: unknown(1); }
│ ^^^^^^^
2 │
ℹ Browsers ignore a declaration that contains an unknown function, so the style is not applied.
ℹ Use a known function instead.
ℹ See MDN web docs for more details.
a { transform: scale(1); }Options
Section titled “Options”ignore
Section titled “ignore”Lists additional function names to allow, without regard to letter case. Defaults to an empty list.
{ "linter": { "rules": { "correctness": { "noUnknownFunction": { "level": "on", "options": { "ignore": [ "custom-function" ] } } } } }}a { transform: custom-function(1); }Related links
Section titled “Related links”Sponsored by
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