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

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

I’ve got several <div> elements on the same level:

<div></div>
<div></div>
<div></div>
<div></div>
<div></div>
<div></div>

I’m trying to use an onclick event to find the event.target‘s previousSiblings until a certain criteria is reached (for example, a class name match) then stop.

How do I achieve this?

Answer

This answer was previously published here in response to a similar question .

There are a few ways to do it.

Either one of the following should do the trick.

// METHOD A (ARRAY.FILTER, STRING.INDEXOF)
var siblings = function(node, children) {
    siblingList = children.filter(function(val) {
        return [node].indexOf(val) != -1;
    });
    return siblingList;
}

// METHOD B (FOR LOOP, IF STATEMENT, ARRAY.PUSH)
var siblings = function(node, children) {
    var siblingList = [];
    for (var n = children.length - 1; n >= 0; n--) {
        if (children[n] != node) {
            siblingList.push(children[n]);
        }  
    }
    return siblingList;
}

// METHOD C (STRING.INDEXOF, ARRAY.SPLICE)
var siblings = function(node, children) {
   siblingList = children;
   index = siblingList.indexOf(node);
   if(index != -1) {
       siblingList.splice(index, 1);
   }
   return siblingList;
}

FYI: The jQuery code-base is a great resource for observing Grade A Javascript.

Here is an excellent tool that reveals the jQuery code-base in a very streamlined way. http://james.padolsey.com/jquery/

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