datatransferitemlist-indexed-getter.html

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This WPT test may be referenced by the following Test IDs:
- /html/editing/dnd/datastore/datatransferitemlist-indexed-getter.html - WPT Dashboard Interop Dashboard

<!DOCTYPE html>

<meta charset="utf-8">

<title>DataTransferItemList indexed property getter and length</title>

<link rel="help" href="https://html.spec.whatwg.org/multipage/dnd.html#the-datatransferitemlist-interface">

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

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

<script>

"use strict";

function itemListWithTwoStrings() {

  const dt = new DataTransfer();

  dt.items.add("hello", "text/plain");

  dt.items.add("<b>hello</b>", "text/html");

  return dt.items;

test(() => {

  // The indexed property getter is declared without an identifier, so it must

  // not be exposed as an operation on the interface prototype object.

  assert_false("item" in DataTransferItemList.prototype, "item");

  assert_array_equals(Object.getOwnPropertyNames(DataTransferItemList.prototype).sort(),

                      ["add", "clear", "constructor", "length", "remove"]);

}, "DataTransferItemList.prototype exposes exactly length, add(), remove() and clear()");

test(() => {

  const items = itemListWithTwoStrings();

  assert_equals(items.length, 2);

  assert_true(items[0] instanceof DataTransferItem, "items[0]");

  assert_true(items[1] instanceof DataTransferItem, "items[1]");

  assert_equals(items[0].type, "text/plain");

  assert_equals(items[1].type, "text/html");

}, "Supported property indices return a DataTransferItem");

test(() => {

  const items = itemListWithTwoStrings();

  assert_equals(items[2], undefined, "index === length");

  assert_equals(items[100], undefined, "index > length");

  assert_equals(items[4294967294], undefined, "index === 2 ** 32 - 2");

  assert_equals(items[4294967295], undefined, "2 ** 32 - 1 is not an array index");

  assert_equals(items[-1], undefined, "negative index");

}, "Unsupported property indices return undefined");

test(() => {

  const items = itemListWithTwoStrings();

  assert_equals(items.length, 2);

  items.remove(0);

  assert_equals(items.length, 1, "after remove()");

  assert_equals(items[0].type, "text/html");

  assert_equals(items[1], undefined);

  items.clear();

  assert_equals(items.length, 0, "after clear()");

  assert_equals(items[0], undefined);

}, "length is the number of items in the drag data store item list");

test(() => {

  const items = itemListWithTwoStrings();

  const descriptor = Object.getOwnPropertyDescriptor(items, 0);

  assert_equals(descriptor.value, items[0], "value");

  assert_false(descriptor.writable, "writable: there is no indexed property setter");

  assert_true(descriptor.enumerable, "enumerable");

  assert_true(descriptor.configurable, "configurable");

  assert_equals(Object.getOwnPropertyDescriptor(items, 2), undefined, "unsupported index");

}, "Indexed properties are enumerable, configurable and non-writable");

test(() => {

  const items = itemListWithTwoStrings();

  assert_array_equals(Object.keys(items), ["0", "1"]);

  assert_array_equals(Array.from(items, item => item.type), ["text/plain", "text/html"]);

}, "Indexed properties are enumerated and iterated in index order");

</script>