Split list of elements into groups

Question

I would like to split list of elements into groups of 4 except one before last that should contain 2 elements only.

x x x x x x x
x x x x x x x
x x x x x    x
x x x x x    x

This will slice into groups of 4 el.:

for ( var i = 0; i < $(".el").length; i+=4 ) {
  $(".el").slice(i, i + 4).wrapAll('<div class="group">');
}

https://jsfiddle.net/p13rcd1c/

What is an approach to make one group to contain only 2 elements?

Answer 1

By calculating the number of groups beforehand, the slice could be adapted if the 'group'-index is the one before last:

var els = $(".el"),grp = 4, cnt = Math.ceil(els.length/grp), rem = els.length % grp, ind = 0;
for(var i = 0; i <= cnt;i++) {
    els.slice(ind, ind += (i==cnt-2 ? rem : grp)).wrapAll('<div class="group">');
}

edit: an alternate version if the total amount can deviate from filling out. This version fills the last group with 4, but fills the one before that with the remainder. (If that is not the intention, and the original code was the required goal, the linked fiddle still contains the original)

var els = $(".el"),grp = 4, cnt = Math.ceil(els.length/grp), rem = els.length % grp, ind = 0;
for(var i = 0; i <= cnt;i++) {
els.slice(ind, ind += (i==cnt-2 ? rem : grp)).wrapAll('<div class="group">');
}

* { margin: 0; padding: 0}

body {
  margin: 10px
}

.el {
  width: 20px;
  height: 10px;
  margin-bottom: 2px;
  background-color: blue;
}

.group {
  float: left;
  margin-left: 2px;
}

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
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fiddle