Center wrapped items in a space-between flexbox

Question

For a navigation section, I want it to use space-between justification. For smaller displays where the navigation might have to wrap, I'd like the items to center themselves, as opposed to sticking to the left when alone on a row.

nav {
  display: flex;
  width: 100%;
  flex-flow: row wrap;
  justify-content: space-between;
}

<nav>
  <div class='item'>
    Item 1 is alone on its row if the window is small, but is not centered.
  </div>
  <div class='item'>
    Item 2 is very much like item 1.
  </div>
</nav>

Codepen demo: https://codepen.io/anon/pen/MmdOMP?editors=1100#0

Answer 1

There can be 2 solutions from my point of view:

1. Use CSS media queries or;
2. JS solution, explained below:

When item is wrapped it takes 100% width, what you need to do is to check on window resize event the width of the item, and if it is 100% relative to the parent element that means it was wrapped, you can add a class at this point and remove it when the statement is false:

function justifyCenter() {
    var navWidth = $("nav").width();
    var itemWidth = $(".item:first-child").width();

    if (navWidth === itemWidth ) {
        $("nav").addClass('justify-center');
    } else {
        $("nav").removeClass('justify-center');
    }
}

Codepen demo: https://codepen.io/anon/pen/WzgpLw