CSSFontFeatureValuesMap: keys() method

{{APIRef("CSSOM")}}{{SeeCompatTable}}

The keys() method of {{domxref("CSSFontFeatureValuesMap")}} instances returns a new map iterator object that contains the [key, value] pairs for each declaration in this CSSFontFeatureValuesMap in insertion order.

Syntax

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

@font-feature-values "MonteCarlo" {
  @swash {
    swishy: 1;
    swashy: 2;
  }
}

JavaScript

// 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

{{Specifications}}

Browser compatibility

{{Compat}}

See also

• Map.prototype.keys()