How to implement “prevUntil” in Vanilla JavaScript without libraries?

Question

I need to implement the functionality of jQuery\'s prevUntil() method in Vanilla JavaScript.

I\'ve got several

elements on the same level:

Answer 1

Just take a look at how jQuery does it.

prevUntil: function( elem, i, until ) {
    return jQuery.dir( elem, "previousSibling", until );
},

Which uses a while / looping function caled dir(). The prevUntil just keeps going until previousSibling is the same as the until element.

dir: function( elem, dir, until ) {
    var matched = [],
        cur = elem[ dir ];

    while ( cur && cur.nodeType !== 9 && (until === undefined || cur.nodeType !== 1 || !jQuery( cur ).is( until )) ) {
        if ( cur.nodeType === 1 ) {
            matched.push( cur );
        }
        cur = cur[dir];
    }
    return matched;
},