CSSFontFeatureValuesMap: set() 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 set() method of CSSFontFeatureValuesMap instances adds a new entry with a specified key and value to this CSSFontFeatureValuesMap, or updates an existing entry if the key already exists.

Syntax

js
set(key, value)

Parameters

key

The key of the entry to add to or modify within the CSSFontFeatureValuesMap object. Can be any value.

value

The value of the entry to add to or modify within the CSSFontFeatureValuesMap object. Must be an integer that matches the index of the alternative font feature.

Return value

The CSSFontFeatureValuesMap object.

Examples

Basic usage

The following example updates the value for swashy and adds a third declaration. 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
function logSwashes(value, key) {
  console.log(`('${key}') = ${value}`);
}
// get the rules
const myRule = document.styleSheets[0].cssRules[0];
// log current swashes
myRule.swash.forEach(logSwashes); // logs "('swishy') = 1", "('swashy') = 2"

// update swash with the key swashy
myRule.swash.set("swashy", 3);
myRule.swash.forEach(logSwashes); // logs "('swishy') = 1", "('swashy') = 3"

// add new swash with the key swooshy
myRule.swash.set("swooshy", 2);
myRule.swash.forEach(logSwashes); // logs "('swishy') = 1", "('swooshy') = 2", "('swashy') = 3"

Specifications

Specification
CSS Fonts Module Level 4
# dom-cssfontfeaturevaluesmap-set

Browser compatibility

desktop mobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
set
Experimental
Chrome – Full support
Chrome 111 (Release date: 2023-03-07)
footnote Full support
Edge – Full support
Edge 111 (Release date: 2023-03-13)
footnote Full support
Firefox – No support
Firefox
footnote No support
Opera – Full support
Opera 97 (Release date: 2023-03-22)
footnote Full support
Safari – No support
Safari
footnote No support
Chrome Android – Full support
Chrome Android 111 (Release date: 2023-03-07)
footnote Full support
Firefox for Android – No support
Firefox for Android
footnote No support
Opera Android – Full support
Opera Android 75 (Release date: 2023-05-17)
footnote Full support
Safari on iOS – No support
Safari on iOS
footnote No support
Samsung Internet – Full support
Samsung Internet 22 (Release date: 2023-07-14)
footnote Full support
WebView Android – Full support
WebView Android 111 (Release date: 2023-03-01)
footnote Full support
WebView on iOS – No support
WebView on iOS
footnote No support

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support
No support
No support
Experimental. Expect behavior to change in the future.

See also