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// Test |Object.hasOwn| on arguments objects.
function testBasic() {
function arg0() { return Object.hasOwn(arguments, 0); }
function arg1() { return Object.hasOwn(arguments, 1); }
function arg100() { return Object.hasOwn(arguments, 100); }
function argn1() { return Object.hasOwn(arguments, -1); }
function argv(i) { return Object.hasOwn(arguments, i); }
for (let i = 0; i < 100; ++i) {
assertEq(arg0(), false);
assertEq(arg0(1), true);
assertEq(arg0(1, 2), true);
assertEq(arg0(1, 2, 3), true);
assertEq(arg0(1, 2, 3, 4), true);
assertEq(arg0(1, 2, 3, 4, 5), true);
assertEq(arg1(), false);
assertEq(arg1(1), false);
assertEq(arg1(1, 2), true);
assertEq(arg1(1, 2, 3), true);
assertEq(arg1(1, 2, 3, 4), true);
assertEq(arg1(1, 2, 3, 4, 5), true);
assertEq(arg100(), false);
assertEq(arg100(1), false);
assertEq(arg100(1, 2), false);
assertEq(arg100(1, 2, 3), false);
assertEq(arg100(1, 2, 3, 4), false);
assertEq(arg100(1, 2, 3, 4, 5), false);
assertEq(argn1(), false);
assertEq(argn1(1), false);
assertEq(argn1(1, 2), false);
assertEq(argn1(1, 2, 3), false);
assertEq(argn1(1, 2, 3, 4), false);
assertEq(argn1(1, 2, 3, 4, 5), false);
assertEq(argv(i & 3), (i&3) <= 0);
assertEq(argv(i & 3, 1), (i&3) <= 1);
assertEq(argv(i & 3, 1, 2), (i&3) <= 2);
assertEq(argv(i & 3, 1, 2, 3), true);
assertEq(argv(i & 3, 1, 2, 3, 4), true);
assertEq(argv(i & 3, 1, 2, 3, 4, 5), true);
}
}
testBasic();
// Modifying |arguments.length| doesn't change the result.
function testOverriddenLength() {
function f(i) {
if (i === 100) {
arguments.length = 100;
}
return Object.hasOwn(arguments, 1);
}
for (let i = 0; i <= 150; ++i) {
assertEq(f(i), false);
}
}
testOverriddenLength();
// Overridden elements are correctly detected.
function testOverriddenElement() {
function f(i) {
if (i === 100) {
arguments[1] = 0;
}
return Object.hasOwn(arguments, 1);
}
for (let i = 0; i <= 150; ++i) {
assertEq(f(i), i === 100);
}
}
testOverriddenElement();
// Deleted elements are correctly detected.
function testDeletedElement() {
function f(i) {
if (i === 100) {
delete arguments[0];
}
return Object.hasOwn(arguments, 0);
}
for (let i = 0; i <= 150; ++i) {
assertEq(f(i), i !== 100);
}
}
testDeletedElement();
// Contrary to most other arguments object optimisations, forwarded arguments
// don't inhibit optimising |Object.hasOwn|.
function testForwardedArg() {
function f(i) {
function closedOver() {
if (i === 100) i = 0;
}
closedOver();
return Object.hasOwn(arguments, 0);
}
for (let i = 0; i <= 150; ++i) {
assertEq(f(i), true);
}
}
testForwardedArg();
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