Question

How can you create an array with from a set of elements with same rel?

Eg:

<a rel='array' id='2' url='aa'></a>
<a rel='array' id='5' url='bb'></a>
<a rel='array' id='8' url='cc'></a>

Array:

[2] > aa
[5] > bb
[8] > cc

I put each URL as value just to use something. But having the IDs ordered should be enough.

How can this be done?

Answer 1

const anchors = document.getElementsByTagName('a'), arr = [];

for (let i = 0; i < anchors.length; i++){
    let current = anchors[i];

    if(current.getAttribute('rel') == 'array') {
        // arr.push(current.getAttribute('url'));
        arr.push({ 'id' : current.id, 'url' : current.getAttribute('url') });
    }
}

http://jsfiddle.net/8ScSH/

---

Or, more succinctly:

const anchors = [...document.getElementsByTagName('a')];
const arrs = anchors.filter(x => x.getAttribute('rel') === 'array')
    .map(x => { return { 'id': x.id, 'url': x.getAttribute('url') } });