CSSFontFeatureValuesMap: keys() method
Limited availability
This feature is not Baseline because it does not work in some of the most widely-used browsers.
The keys() method of CSSFontFeatureValuesMap instances returns a new map iterator object that contains the [key, value] pairs for each declaration in this CSSFontFeatureValuesMap in insertion order.
Syntax
js
keys()
Parameters
None.
Return value
A new iterable iterator object.
Examples
Basic usage
The following example assigns the keys to the swashKeys variable and then logs the first two values. This example is using @swash but also works with other feature value blocks.
CSS
css
@font-feature-values "MonteCarlo" {
@swash {
swishy: 1;
swashy: 2;
}
}
JavaScript
js
// get the rules
const myRule = document.styleSheets[0].cssRules[0];
// get the keys of swash
const swashKeys = myRule.swash.keys();
console.log(swashKeys.next().value); // logs "swishy"
console.log(swashKeys.next().value); // logs "swashy"
Specifications
| Specification |
|---|
| CSS Fonts Module Level 4 # cssfontfeaturevaluesmap |