registered-properties-inheritance.html

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This WPT test may be referenced by the following Test IDs:
- /css/css-properties-values-api/registered-properties-inheritance.html - WPT Dashboard Interop Dashboard

<!DOCTYPE HTML>

<link rel="help" href="https://drafts.css-houdini.org/css-properties-values-api/#dom-propertydescriptor-inherits" />

<link rel="help" href="https://drafts.css-houdini.org/css-properties-values-api/#register-a-custom-property" />

<script src="/resources/testharness.js"></script>

<script src="/resources/testharnessreport.js"></script>

<style>

#outer {

    --inherited-length-1: 10px;

    --inherited-length-2: var(--non-inherited-length-1);

    --inherited-length-3: 30px;

    --non-inherited-length-1: 22px;

    --non-inherited-length-3: calc(var(--non-inherited-length-2) * 10);

#inner {

    --inherited-length-3: 15px;

    --non-inherited-length-1: 40px;

    --non-inherited-length-2: 90px;

</style>

<div id=outer><div id=inner></div></div>

<script>

test(function() {

    CSS.registerProperty({name: '--inherited-length-1', syntax: '<length>', initialValue: '1px', inherits: true});

    CSS.registerProperty({name: '--inherited-length-2', syntax: '<length>', initialValue: '2px', inherits: true});

    CSS.registerProperty({name: '--inherited-length-3', syntax: '<length>', initialValue: '3px', inherits: true});

    CSS.registerProperty({name: '--non-inherited-length-1', syntax: '<length>', initialValue: '4px', inherits: false});

    CSS.registerProperty({name: '--non-inherited-length-2', syntax: '<length>', initialValue: '5px', inherits: false});

    CSS.registerProperty({name: '--non-inherited-length-3', syntax: '<length>', initialValue: '6px', inherits: false});

    outerComputedStyle = getComputedStyle(outer);

    assert_equals(outerComputedStyle.getPropertyValue('--inherited-length-1'), '10px');

    assert_equals(outerComputedStyle.getPropertyValue('--inherited-length-2'), '22px');

    assert_equals(outerComputedStyle.getPropertyValue('--inherited-length-3'), '30px');

    assert_equals(outerComputedStyle.getPropertyValue('--non-inherited-length-1'), '22px');

    assert_equals(outerComputedStyle.getPropertyValue('--non-inherited-length-2'), '5px');

    assert_equals(outerComputedStyle.getPropertyValue('--non-inherited-length-3'), '50px');

    innerComputedStyle = getComputedStyle(inner);

    assert_equals(innerComputedStyle.getPropertyValue('--inherited-length-1'), '10px');

    assert_equals(innerComputedStyle.getPropertyValue('--inherited-length-2'), '22px');

    assert_equals(innerComputedStyle.getPropertyValue('--inherited-length-3'), '15px');

    assert_equals(innerComputedStyle.getPropertyValue('--non-inherited-length-1'), '40px');

    assert_equals(innerComputedStyle.getPropertyValue('--non-inherited-length-2'), '90px');

    assert_equals(innerComputedStyle.getPropertyValue('--non-inherited-length-3'), '6px');

}, "Registered properties are correctly inherited (or not) depending on the inherits flag.");

test(function(){

    CSS.registerProperty({name: '--initial-length-1', syntax: '<length>', initialValue: '0px', inherits: false});

    outer.style = '--initial-length-1: notalength';

    inner.style = '--initial-length-1: inherit';

    assert_equals(getComputedStyle(inner).getPropertyValue('--initial-length-1'), '0px');

}, "Explicitly inheriting from a parent with an invalid value results in initial value.");

test(function(){

    CSS.registerProperty({name: '--initial-length-2', syntax: '<length>', initialValue: '0px', inherits: false});

    inner.style = '--initial-length-2: inherit';

    assert_equals(getComputedStyle(inner).getPropertyValue('--initial-length-2'), '0px');

}, "Explicitly inheriting from a parent with no value results in initial value.");

test(function(){

    CSS.registerProperty({name: '--initial-length-3', syntax: '<length>', initialValue: '0px', inherits: false});

    outer.style = '--initial-length-3: 100px';

    inner.style = '--initial-length-3: inherit';

    assert_equals(getComputedStyle(inner).getPropertyValue('--initial-length-3'), '100px');

}, "Explicitly inheriting from a parent with a value results in that value.");

test(function(){

    CSS.registerProperty({name: '--inherited-length-4', syntax: '<length>', initialValue: '0px', inherits: true});

    outer.style = '--inherited-length-4: 42px';

    inner.style = '--inherited-length-4: var(--undefined)';

    assert_equals(getComputedStyle(inner).getPropertyValue('--inherited-length-4'), '42px');

}, "Reference to undefined variable results in inherited value");

test(function(){

    CSS.registerProperty({name: '--inherited-length-5', syntax: '<length>', initialValue: '0px', inherits: true});

    outer.style = '--inherited-length-5: 42px';

    inner.style = '--incompatible: nolength; --inherited-length-5: var(--incompatible)';

    assert_equals(getComputedStyle(inner).getPropertyValue('--inherited-length-5'), '42px');

}, "Reference to syntax-incompatible variable results in inherited value");

test(function(){

    CSS.registerProperty({name: '--inherited-em', syntax: '<length>', initialValue: '0px', inherits: true});

    outer.style = 'font-size: 11px; --inherited-em: 10em;';

    inner.style = 'font-size: 22px; --unregistered:var(--inherited-em);';

    assert_equals(getComputedStyle(inner).getPropertyValue('--unregistered'), '110px');

}, "Font-relative units are absolutized before before inheritance");

test(function(){

    CSS.registerProperty({name: '--calc-length', syntax: '<length>', initialValue: '0px', inherits: true});

    outer.style = '--calc-length: calc(10px + 10px);';

    inner.style = '--unregistered:var(--calc-length);';

    assert_equals(getComputedStyle(inner).getPropertyValue('--unregistered'), '20px');

}, "Calc expressions are resolved before inheritance");

</script>