Array.prototype.shift() 和pop() 有类似的行为,但是它是作用在数组的第一个元素上的。 pop() 是修改方法。其改变了 this 的长度和内容。如果你想要 this 不变,但是返回一个新的最后一个元素被移除的数组,你可以使用 arr.slice(0, -1) 来代替。 pop() 方法是通用的。它只期望 this 值具有
This will create a pseudo-propertylatestfor objectobj, which will return the last array item inlog. var log = ['test']; var obj = { get latest () { if (log.length == 0) return undefined; return log[log.length - 1] } } console.log (obj.latest); // Will return "test". ...
Returns the item in the list by its index, or null if the index is greater than or equal to the list's length. DOMTokenList.contains() Returns true if the list contains the given token, otherwise false. DOMTokenList.add() Adds the specified tokens to the list. DOMTokenList.remove()...
Bear in mind that you can store any item in an array — string, number, object, another variable, even another array. You can also mix and match item types — they don't all have to be numbers, strings, etc, just like this: var random = ['tree', 795, [0, 1, 2]];. 字符串...
{ 38 let myItem = input.value; 39 input.value = ''; 40 41 const listItem = document.createElement('li'); 42 const listText = document.createElement('span'); 43 const listBtn = document.createElement('button'); 44 45 listItem.appendChild(listText); 46 listText.textContent = myItem; ...
[playerItem addObserver:self forKeyPath:@"status" options:NSKeyValueObservingOptionNew context:nil]; //监控网络加载情况属性 [playerItem addObserver:self forKeyPath:@"loadedTimeRanges" options:NSKeyValueObservingOptionNew context:nil]; } -(void)removeObserverFromPlayerItem:(AVPlayerItem *)playerItem{...
readonly attribute boolean hasDisjointDates; void setDateList(in unsigned long aCount, [array,size_is(aCount)] in calIDateTime aDates); void getDateList(out unsigned long aCount, [array,size_is(aCount),retval] out calIDateTime aDates); attribute calIItemBase selectedItem; attribute calIDateTi...
Remove empty sections #38515 Open Josh-Cena wants to merge 1 commit into mdn:main from Josh-Cena:rm-empty-section+16 −56 Conversation 1 Commits 1 Checks 7 Files changed 34 Conversation Member Josh-Cena commented Mar 7, 2025 Similar to #38506 Remove empty sections 7527d97 Josh-...
1. Add a new prop to your `ToDoItem` component — `id`. 2. Make it required, and make its type a `String`. 3. To prevent name collisions, remove the `id` field from your `data` attribute. 4. You are no longer using `uniqueId`, so you need to remove the `import uniqueId ...
Item *backItem;//获取某个index的网页节点- (nullable WKBackForwardListItem *)itemAtIndex:(NSInteger)index;//获取回退的节点数组@property (nonatomic,readonly, copy) NSArray<WKBackForwardListItem *> *backList;//获取前进的节点数组@property (nonatomic,readonly, copy) NSArray<WKBackForwardListItem ...