custom-elements/state/state-css-selector.html

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <meta name="timeout" content="long">
    <meta name="author" title="Keith Cirkel" href="mailto:wpt@keithcirkel.co.uk" />
    <link rel="help" href="https://html.spec.whatwg.org/multipage/custom-elements.html#custom-state-pseudo-class" />
    <title>:state() css selector applies</title>

    <script src="/resources/testharness.js"></script>
    <script src="/resources/testharnessreport.js"></script>
  </head>
  <body>
    <custom-state id="myCE">I should be green</custom-state>
    <p id="mySibling">I should be blue</p>
    <p id="myHas">I should be blue</p>
    <style>
      custom-state {
        color: #f00;
      }
      custom-state + p {
        color: #f00;
      }
      custom-state:state(--green) {
        color: #0f0;
      }
      custom-state:--green {
        color: #0f0;
      }
      body:has(custom-state:state(--green)) p {
        color: #0ff;
      }
      custom-state:state(--green) + p[id] {
        color: #00f;
      }
      custom-state:--green + p {
        color: #00f;
      }
    </style>
    <script>
    customElements.define('custom-state', class extends HTMLElement {
      connectedCallback() {
        this.elementInternals = this.attachInternals();
      }
    });

    test(function() {
        assert_false(myCE.elementInternals.states.has('--green'));
        assert_equals(getComputedStyle(myCE).getPropertyValue('color'), 'rgb(255, 0, 0)');
    }, "state selector has no influence when state is not applied");

    test(function() {
        assert_false(myCE.elementInternals.states.has('--green'));
        assert_equals(getComputedStyle(mySibling).getPropertyValue('color'), 'rgb(255, 0, 0)');
    }, "state selector has no influence on sibling selectors when not applied");

    test(function(t) {
        myCE.elementInternals.states.add('--green');
        t.add_cleanup(() => { myCE.elementInternals.states.delete('--green') });
        assert_true(myCE.elementInternals.states.has('--green'));
        assert_equals(getComputedStyle(myCE).getPropertyValue('color'), 'rgb(0, 255, 0)');
    }, "state selector has influence when state is applied");

    test(function(t) {
        myCE.elementInternals.states.add('--green');
        t.add_cleanup(() => { myCE.elementInternals.states.delete('--green') });
        assert_true(myCE.elementInternals.states.has('--green'));
        assert_equals(getComputedStyle(mySibling).getPropertyValue('color'), 'rgb(0, 0, 255)');
    }, "state selector influences siblings when state is applied");

    test(function(t) {
        myCE.elementInternals.states.add('--green');
        t.add_cleanup(() => { myCE.elementInternals.states.delete('--green') });
        assert_true(myCE.elementInternals.states.has('--green'));
        assert_equals(getComputedStyle(myHas).getPropertyValue('color'), 'rgb(0, 255, 255)');
    }, "state selector influences has() when state is applied");

    test(function(t) {
        myCE.elementInternals.states.add('--foo');
        t.add_cleanup(() => { myCE.elementInternals.states.delete('--foo') });
        assert_false(myCE.elementInternals.states.has('--green'));
        assert_true(myCE.elementInternals.states.has('--foo'));
        assert_equals(getComputedStyle(myCE).getPropertyValue('color'), 'rgb(255, 0, 0)');
    }, "state selector only applies on given ident");

    test(function(t) {
        myCE.elementInternals.states.add('--foo');
        t.add_cleanup(() => { myCE.elementInternals.states.delete('--foo') });
        assert_false(myCE.elementInternals.states.has('--green'));
        assert_true(myCE.elementInternals.states.has('--foo'));
        assert_equals(getComputedStyle(mySibling).getPropertyValue('color'), 'rgb(255, 0, 0)');
    }, "state selector only applies to siblings on given ident");

    test(function(t) {
        myCE.elementInternals.states.add('--foo');
        t.add_cleanup(() => { myCE.elementInternals.states.delete('--foo') });
        assert_false(myCE.elementInternals.states.has('--green'));
        assert_true(myCE.elementInternals.states.has('--foo'));
        assert_equals(getComputedStyle(mySibling).getPropertyValue('color'), 'rgb(255, 0, 0)');
    }, "state selector only applies to has() on given ident");

    test(function(t) {
        myCE.elementInternals.states.add('--green');
        myCE.elementInternals.states.add('--green');
        myCE.elementInternals.states.add('--green');
        t.add_cleanup(() => { myCE.elementInternals.states.delete('--green') });
        assert_true(myCE.elementInternals.states.has('--green'));
        assert_equals(getComputedStyle(myCE).getPropertyValue('color'), 'rgb(0, 255, 0)');
        assert_true(myCE.elementInternals.states.delete('--green'));
        assert_false(myCE.elementInternals.states.has('--green'));
        assert_equals(getComputedStyle(myCE).getPropertyValue('color'), 'rgb(255, 0, 0)');
        assert_false(myCE.elementInternals.states.delete('--green'));
    }, "states added multiple times counts as one");

    test(function(t) {
        myCE.elementInternals.states.add('--green');
        myCE.elementInternals.states.add('--foo');
        t.add_cleanup(() => { myCE.elementInternals.states.clear() });
        assert_true(myCE.elementInternals.states.has('--green'));
        assert_true(myCE.elementInternals.states.has('--foo'));
        assert_equals(getComputedStyle(myCE).getPropertyValue('color'), 'rgb(0, 255, 0)');
        myCE.elementInternals.states.clear();
        assert_false(myCE.elementInternals.states.has('--green'));
        assert_false(myCE.elementInternals.states.has('--foo'));
        assert_equals(getComputedStyle(myCE).getPropertyValue('color'), 'rgb(255, 0, 0)');
    }, "style is invalided on clear()");

    </script>
  </body>
</html>