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Test Info:
<!DOCTYPE HTML>
<html>
<head>
<meta charset="utf-8">
<title>Test WeakRef works in the browser</title>
<script src="/tests/SimpleTest/SimpleTest.js"></script>
<script type="application/javascript">
let wr1, wr2, wr3, wr4;
function go() {
SimpleTest.waitForExplicitFinish();
// 1. WeakRef with JS target.
wr1 = new WeakRef({});
// 2. WeakRef with DOM object target (without preserved wrapper).
wr2 = new WeakRef(document.createElement("div"));
// 3. WeakRef with DOM object target (with preserved wrapper).
let object = document.createElement("div");
object.someProperty = true;
wr3 = new WeakRef(object);
object = null
// 4. WeakRef with reachable DOM object target without preserved wrapper.
document.body.appendChild(document.createElement("div"));
wr4 = new WeakRef(document.body.lastChild);
// WeakRef should keep the target in the current task.
isnot(wr1.deref(), undefined, "deref() should return its target.");
isnot(wr2.deref(), undefined, "deref() should return its target.");
isnot(wr3.deref(), undefined, "deref() should return its target.");
isnot(wr4.deref(), undefined, "deref() should return its target.");
// WeakRef should keep the target until the end of current task, which
// includes promise microtasks.
Promise.resolve().then(() => {
isnot(wr1.deref(), undefined, "deref() should return its target.");
isnot(wr2.deref(), undefined, "deref() should return its target.");
isnot(wr3.deref(), undefined, "deref() should return its target.");
isnot(wr4.deref(), undefined, "deref() should return its target.");
});
// setTimeout will call its callback in a new task.
setTimeout(task2, 0);
}
function task2() {
// Trigger a full GC/CC/GC cycle to collect WeakRef targets.
SpecialPowers.DOMWindowUtils.garbageCollect();
SpecialPowers.DOMWindowUtils.cycleCollect();
SpecialPowers.DOMWindowUtils.garbageCollect();
is(wr1.deref(), undefined, "deref() should return undefined.");
is(wr2.deref(), undefined, "deref() should return undefined.");
is(wr3.deref(), undefined, "deref() should return undefined.");
isnot(wr4.deref(), undefined, "deref() should return its target.");
// setTimeout will call its callback in a new task.
setTimeout(task3, 0);
}
function task3() {
document.body.removeChild(document.body.lastChild);
SpecialPowers.DOMWindowUtils.garbageCollect();
SpecialPowers.DOMWindowUtils.cycleCollect();
SpecialPowers.DOMWindowUtils.garbageCollect();
is(wr1.deref(), undefined, "deref() should return undefined.");
is(wr2.deref(), undefined, "deref() should return undefined.");
is(wr3.deref(), undefined, "deref() should return undefined.");
is(wr4.deref(), undefined, "deref() should return undefined.");
SimpleTest.finish();
}
</script>
</head>
<body onload="go()"></body>
</html>