Javascript Javascript将项目添加到当前数组
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Javascript add item to current array
提问by Vinay
I am trying to add an item to a current array.
我正在尝试向当前数组添加一个项目。
var arrayValues = new Array();
arrayValues.push("Value 1");
arrayValues.push("Value 2");
arrayValues = document.getElementsByTagName('a');
arrayValues.push("Value 3");
By doing this way I get a error, and I dont get value 1 and value 2, after getting the hyperlink collection when I try to add a new item it throws Error: Object doesn't support this property or method which is the push method.
通过这样做，我得到一个错误，我没有得到值 1 和值 2，当我尝试添加一个新项目时获取超链接集合后，它抛出错误：对象不支持此属性或方法，即 push 方法.
What is happening to the array after the collection of hyperlinks is assigned ? How can I add a new item to it ?
分配超链接集合后数组发生了什么？如何向其中添加新项目？
回答by Matt Ball
Did you mean arrayValues.push(document.getElementsByTagName('a'));?
你的意思是arrayValues.push(document.getElementsByTagName('a'));？
Otherwise, you're assigning the NodeListreturned by getElementsByTagName(), which overwrites the array you had just pushed values into.
否则，您将分配NodeList返回的 by getElementsByTagName()，它会覆盖您刚刚将值推入的数组。
Side note: there's no reason to use new Array()here. Just write var arrayValues = [];.
旁注：没有理由在new Array()这里使用。只是写var arrayValues = [];。
回答by Thai
If you want to push all <a>elements to the array, you have to convert the NodeList to an array first. Most people use Array.prototype.slice.call(nodelist).
如果要将所有<a>元素推送到数组，则必须先将 NodeList 转换为数组。大多数人使用Array.prototype.slice.call(nodelist).
Once you have an array, you can then use array.pushin conjunction with function.applyto push them in one call.
一旦你有了一个数组，你就可以array.push结合使用function.apply在一次调用中推送它们。
The resulting code looks like:
生成的代码如下所示：
var arrayValues = [];
arrayValues.push("Value 1");
arrayValues.push("Value 2");
arrayValues.push.apply(arrayValues, Array.prototype.slice.call(document.getElementsByTagName('a')));
arrayValues.push("Value 3");
