offscreencanvas.constructor.html

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This WPT test may be referenced by the following Test IDs:
- /html/canvas/offscreen/manual/the-offscreen-canvas/offscreencanvas.constructor.html - WPT Dashboard Interop Dashboard

<!DOCTYPE html>

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

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

<script src="/html/canvas/resources/canvas-tests.js"></script>

<link rel="help" href="https://html.spec.whatwg.org/#dom-offscreencanvas">

<script>

test(function() {

  assert_throws_js(

    TypeError,

    () => OffscreenCanvas(100, 50),

    "Calling OffscreenCanvas constructor without 'new' must throw"

);

}, "OffscreenCanvas constructor called as normal function");

test(function() {

    var offscreenCanvas = new OffscreenCanvas(100, 50);

    assert_equals(offscreenCanvas.width, 100);

    assert_equals(offscreenCanvas.height, 50);

    offscreenCanvas.width = 50;

    offscreenCanvas.height = 100;

    assert_equals(offscreenCanvas.width, 50);

    assert_equals(offscreenCanvas.height, 100);

}, "Test that calling OffscreenCanvas's constructor generates correct width and height.");

test(function() {

    var offscreenCanvas1 = new OffscreenCanvas(1, 1);

    offscreenCanvas1.width = null;

    offscreenCanvas1.height = null;

    assert_equals(offscreenCanvas1.width, 0);

    assert_equals(offscreenCanvas1.height, 0);

    assert_throws_js(TypeError, function() { new OffscreenCanvas(-1, -1); });

    var offscreenCanvas2 = new OffscreenCanvas(null, null);

    assert_equals(offscreenCanvas2.width, 0);

    assert_equals(offscreenCanvas2.height, 0);

    assert_throws_js(TypeError, function() { offscreenCanvas2.width = -1; });

    assert_throws_js(TypeError, function() { offscreenCanvas2.height = -1; });

    var obj = {Name: "John Doe", Age: 30};

    assert_throws_js(TypeError, function() { offscreenCanvas2.width = obj; });

    assert_throws_js(TypeError, function() { offscreenCanvas2.height = obj; });

    assert_throws_js(TypeError, function() { new OffscreenCanvas(obj, obj); });

}, "Test that OffscreenCanvas constructor handles invalid arguments correctly");

</script>