HighlightRegistry: keys() method
Baseline
2025
Newly available
Since June 2025, this feature works across the latest devices and browser versions. This feature might not work in older devices or browsers.
The keys() method of the HighlightRegistry interface returns a new Iterator object that contains the keys for each Highlight object in the HighlightRegistry object in insertion order.
HighlightRegistry is a Map-like object, so this is similar to using Map.keys().
Syntax
keys()
Parameters
None.
Return value
A new iterator object containing the names of each Highlight object in the registry, in insertion order.
Examples
The following code snippet shows how to create and register three Highlight objects, and use the iterator returned by the keys() method to log their names:
const fooHighlight = new Highlight();
const barHighlight = new Highlight();
const bazHighlight = new Highlight();
CSS.highlights.set("foo", fooHighlight);
CSS.highlights.set("bar", barHighlight);
CSS.highlights.set("baz", bazHighlight);
const iter = CSS.highlights.keys();
console.log(iter.next().value); // "foo"
console.log(iter.next().value); // "bar"
console.log(iter.next().value); // "baz"
The following code example shows how to iterate over the highlights in the registry by using a for...of loop:
const fooHighlight = new Highlight();
const barHighlight = new Highlight();
const bazHighlight = new Highlight();
CSS.highlights.set("foo", fooHighlight);
CSS.highlights.set("bar", barHighlight);
CSS.highlights.set("baz", bazHighlight);
for (const name of CSS.highlights.keys()) {
console.log(name);
}
Specifications
| Specification |
|---|
| ECMAScript® 2026 Language Specification # sec-map.prototype.keys |
Browser compatibility
Loading…