title: Expand multiple flexbox items to fit container width
body: <p>I have a layout where I want to make the breadcrumb trail use up all of the available space in the row. In the same row I also have a div (.tools) which needs to be of a dynamic width as it's contents may vary.</p>
  
  <p>At the moment I have to set the breadcrumb trail to a % width to get it to work roughly correctly, but this isn't ideal... I'd like it to just expand to fill the available space.</p>
  
  <p>Any ideas?</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-css lang-css prettyprint-override"><code>header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 20px;
    background-color: lightgreen;
    width: 100%;
    box-sizing: border-box;
  }
  
  .breadcrumb {
    display: flex;
    align-items: center;
    justify-content: flex-start;
    white-space: nowrap;
    width: 55%;
    background-color: lightblue;
  }
  
  .breadcrumbItem {
    display: flex;
    flex: 0 10 auto;
    min-width: 45px;
    align-items: center;
    overflow: hidden;
    text-overflow: ellipsis;
  }
  .breadcrumbItem button {
    border: 0;
    background: none;
    padding: 0 5px;
    flex: 0 1 auto;
    white-space: nowrap;
    width: 100%;
    overflow: hidden;
    text-overflow: ellipsis;
  }
  
  .tools {
    display: flex;
    justify-content: flex-end;
    background-color: lightyellow;
  }
  .tools span, .tools button {
    white-space: nowrap;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;header&gt;
    &lt;div class="breadcrumb"&gt;
      &lt;div class="breadcrumbItem"&gt;
        &lt;button&gt;Really long breadcrumb item here&lt;/button&gt;
        &lt;span&gt;
          &lt;span&gt;&gt;&lt;/span&gt;
        &lt;/span&gt;
      &lt;/div&gt;
      &lt;div class="breadcrumbItem"&gt;
        &lt;button&gt;Another really long item that should ellipse when it gets too long, oidsf jsodifj dsoifj sdoifj sdoifj sdoifj sdoifj sdoifj sdoifj dsoifj sdoifj sd&lt;/button&gt;
      &lt;/div&gt;
    &lt;/div&gt;
    &lt;div class="tools"&gt;
      &lt;span&gt;0 photos selected&lt;/span&gt;
      &lt;button&gt;Button&lt;/button&gt;
    &lt;/div&gt;
  &lt;/header&gt;</code></pre>
  </div>
  </div>
  </p>
  
  <p><a href="https://codepen.io/anon/pen/NYaQyV" rel="nofollow noreferrer">https://codepen.io/anon/pen/NYaQyV</a></p>