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HighlightRegistry: keys() method

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

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

js

keys()

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:

js

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:

js

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 Language Specification
# sec-map.prototype.keys

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
keys 105 105 preview No 91 No 105 105 No 72 No 20.0

See also

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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/HighlightRegistry/keys