CODEWITHSUNDEEP
javascriptjquery
Royi Namir
Royi Namir

Reputation: 148554

parentsUntil() in jQuery uses reversed order?

I have this html structure : 

<body>
  <a>
    <b>
      <c>
        <d>
        </d>
      </c>
    </b>
  </a>
</body>

I use the <d> element as the first node to start with.

Question :

 var s= $("d").parentsUntil("body").andSelf().map(function(){
    return this.tagName;
  }).get();

It should start from the bottom and to top meaning the s array should look like d,c,b,a.

But it apparently look like : ["A", "B", "C", "D"]

Why is that ?

Jsbin

Upvotes: 3

Views: 410

Answers (2)

Denys S&#233;guret
Denys S&#233;guret

Reputation: 382170

If you look at addBack's code (to which andSelf is an alias), you see this :

add: function( selector, context ) {
    var set = typeof selector === "string" ?
            jQuery( selector, context ) :
            jQuery.makeArray( selector && selector.nodeType ? [ selector ] : selector ),
        all = jQuery.merge( this.get(), set );

    return this.pushStack( jQuery.unique(all) );
},

addBack: function( selector ) {
    return this.add( selector == null ?
        this.prevObject : this.prevObject.filter(selector)
    );
}

So you see it calls unique.

By looking further, you see

jQuery.unique = Sizzle.uniqueSort;

and

Sizzle.uniqueSort = function( results ) {
    var elem,
        duplicates = [],
        i = 1,
        j = 0;

    // Unless we *know* we can detect duplicates, assume their presence
    hasDuplicate = !support.detectDuplicates;
    results.sort( sortOrder );

    if ( hasDuplicate ) {
        for ( ; (elem = results[i]); i++ ) {
            if ( elem === results[ i - 1 ] ) {
                j = duplicates.push( i );
            }
        }
        while ( j-- ) {
            results.splice( duplicates[ j ], 1 );
        }
    }

    return results;
};

So, addBack sorts the set as it ensures the added element isn't yet inside.

Upvotes: 1

pktangyue
pktangyue

Reputation: 8524

.andSelf() causes jQuery to re-order the array.

You can try :

 var s= $("d").parentsUntil("body").map(function(){
    return this.tagName;
  }).get();

The output of this code looks like:["C", "B","A" ].

Upvotes: 3

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