CODEWITHSUNDEEP
javascriptarrayscollections
mplungjan
mplungjan

Reputation: 177885

collection item() vs array []

Apologies if this is a duplicate - it is not easy to search for.

I have today come across TWO questions using someArrayOrCollection.item(i) instead of my preferred someArrayOrCollection[i]

Example: parse XML attribute value using javascript

var sTitle1 = item.getElementsByTagName("title").item(0)....

where I would use

var sTitle1 = item.getElementsByTagName("title")[0]....

Last time I saw these where when only IE supported that notation.

My first instinct when I see .item() is to correct it to []. Should I or is it harmless or perhaps even best practice these days?

Interestingly almost all the collections at MDN mentions the item method but their examples use [] - for example https://developer.mozilla.org/en-US/docs/Web/API/NodeList

Upvotes: 2

Views: 637

Answers (1)

georg
georg

Reputation: 214959

For NamedNodeMaps [] acts as a sugar for both .item and .getNamedItem, which makes it possible to build a contrived example where index will be different from .item:

<div id="x" 2e0="wtf" class="foo" ></div>

<script>
a = document.getElementById("x").attributes;
console.log(a["2e0"].nodeValue)         // wtf
console.log(a.item("2e0").nodeValue)    // foo
</script>

Needless to say, this is purely theoretical, in the real life [] is a safe choice.

Upvotes: 4

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