CSSFontFeatureValuesMap: has() method
Limited availability
This feature is not Baseline because it does not work in some of the most widely-used browsers.
Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.
The has() method of the CSSFontFeatureValuesMap interface returns a boolean indicating whether an entry with the specified key exists in this CSSFontFeatureValuesMap or not.
Syntax
has(property)
Parameters
key-
The key of the value to return from the
CSSFontFeatureValuesMapobject.
Return value
The value associated with the specified key in the CSSFontFeatureValuesMap object. If the key can't be found, undefined is returned.
Examples
Basic usage
The following example returns true or false if the @swash rule contains the key. This example is using @swash but also works with other feature value blocks.
CSS
@font-feature-values "MonteCarlo" {
@swash {
swishy: 1;
swashy: 2;
}
}
JavaScript
// get the rules
const myRule = document.styleSheets[0].cssRules[0];
console.log(myRule.swash.has("swishy")); // logs true
console.log(myRule.swash.has("swooshy")); // logs false
Specifications
| Specification |
|---|
| CSS Fonts Module Level 4 # cssfontfeaturevaluesmap |