Javascript add item to current array

Question

I am trying to add an item to a current array.

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.

What is happening to the array after the collection of hyperlinks is assigned ? How can I add a new item to it ?

Answer 1

Did you mean arrayValues.push(document.getElementsByTagName('a'));?

Otherwise, you're assigning the NodeList returned by getElementsByTagName(), which overwrites the array you had just pushed values into.

Side note: there's no reason to use new Array() here. Just write var arrayValues = [];.

Answer 2

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).

Once you have an array, you can then use array.push in conjunction with function.apply to push them in one call.

The resulting code looks like:

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");