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

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"