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Test Info:
- This WPT test may be referenced by the following Test IDs:
- /html/editing/dnd/datastore/datatransfer-types.html - WPT Dashboard Interop Dashboard
<!DOCTYPE html>
<meta charset="utf-8">
<title>DataTransfer types attribute test</title>
<link rel="help" href="https://html.spec.whatwg.org/multipage/interaction.html#the-datatransfer-interface">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script>
test(() => {
const dt = new DataTransfer();
assert_true(Object.isFrozen(dt.types), "types must be a FrozenArray<>");
assert_true(Array.isArray(dt.types), "A FrozenArray<> must be an Array");
assert_equals(dt.types.length, 0, "types must be originally empty");
assert_equals(dt.types, dt.types,
"types must return the same object when the data store item list has not changed");
const dt2 = new DataTransfer();
assert_not_equals(dt2.types, dt.types,
"Different DataTransfer objects must return different FrozenArrays");
}, "type's state on DataTransfer creation");
test(() => {
const dt = new DataTransfer();
dt.setData("text/plain", "foo");
let old_types = dt.types;
assert_equals(old_types, dt.types);
// Clearing the data store via DataTransferItemList changes
// DataTransfer's data store, so types will return a new FrozenArray.
dt.items.clear();
assert_not_equals(old_types, dt.types);
// Clearing an empty list does not change it.
old_types = dt.types;
dt.items.clear();
assert_equals(old_types, dt.types);
// Removing a non-existent item from the data store does not change it.
dt.setData("text/plain", "foo");
old_types = dt.types;
dt.items.remove(42);
assert_equals(old_types, dt.types);
// Removing a valid item from the data store changes it.
dt.items.remove(0);
assert_equals(dt.items.length, 0);
assert_not_equals(old_types, dt.types);
// Adding a new item to the list changes it, types will return a new
// FrozenArray.
old_types = dt.types;
dt.items.add("foo", "text/plain");
assert_equals(dt.items.length, 1);
assert_not_equals(old_types, dt.types);
// Failing to add a new item via DataTransferItemList does not
// change the underlying data store.
old_types = dt.types;
assert_throws_dom("NotSupportedError", () => {
dt.items.add("bar", "text/plain");
}, "Adding an item whose type is already present throws an exception");
assert_equals(dt.items.length, 1);
assert_equals(old_types, dt.types);
}, "Relationship between types and items");
test(() => {
const dt = new DataTransfer();
dt.setData("text/plain", "foo");
let old_types = dt.types;
assert_equals(old_types, dt.types);
// Replacing the text/plain item causes the underlying data store item list
// to change, so types will return a new FrozenArray.
dt.setData("text/plain", "bar");
assert_equals(dt.types.length, 1);
assert_not_equals(old_types, dt.types);
old_types = dt.types;
// Adding a new item causes the underlying data store item list to change, so
// types will return a new FrozenArray.
dt.setData("text/uri-list", "baz quux");
assert_equals(dt.types.length, 2);
assert_not_equals(old_types, dt.types);
// Removing the text/uri-list item causes the underlying data store item list
// to change, so even though the item list only has a text/plain item, types
// will return a new FrozenArray that does not match |old_types|.
dt.clearData("text/uri-list");
assert_equals(dt.types.length, 1);
assert_not_equals(old_types, dt.types);
old_types = dt.types;
// This clearData() call did not change the underlying item list, so types is
// still the same as |old_types|.
dt.clearData("text/uri-list");
assert_equals(dt.types.length, 1);
assert_equals(old_types, dt.types);
dt.clearData();
old_types = dt.types;
// Clearing an already empty list does not change the underlying item list,
// so types is stil the same as |old_types|.
dt.clearData();
assert_equals(old_types, dt.types);
}, "type's identity");
test(() => {
const dt = new DataTransfer();
const types = dt.types;
dt.types = 42;
assert_equals(dt.types, types);
}, "Verify type is a read-only attribute");
test(() => {
const dt = new DataTransfer();
assert_array_equals(dt.types, []);
// The added File is respected
dt.items.add(new File(["abc"], "test.txt"));
assert_array_equals(dt.types, ["Files"]);
// "Files" is always last even after setting data
dt.setData("text/plain", "test");
assert_array_equals(dt.types, ["text/plain", "Files"]);
// Removing the File changes types
dt.items.remove(0);
assert_array_equals(dt.types, ["text/plain"]);
// Adding back a File as the second item works correctly.
dt.items.add(new File(["abc"], "test.txt"));
assert_array_equals(dt.types, ["text/plain", "Files"]);
}, "DataTransfer containing files");
</script>