Is it possible to get Flexbox to work inside label?

Question

I'm using flexbox to display a text label along with a numeric value in a narrow column, so that the text is truncated with ellipsis if it doesn't fit.

It worked fine, until I had the need to place the entire column in a table-cell - at which point the browser (Chrome) just ignored the column width and made the table wide enough to fit all the text.

Here's the label layout:

<div class="line">
    <span>Very long label text</span>
    <span>12345</span>
</div>

.line {
    display: flex;
    width: 100%;
}
.line span:first-child {
    white-space: nowrap;
    flex-grow: 1;
    overflow: hidden;
    text-overflow: ellipsis;
}
.line span:last-child {
    flex-shrink: 0;
    margin-left: 5px;
}

Placing it in a regular div with a fixed width works as expected. Placing it in a table-cell doesn't:

Fiddle: http://jsfiddle.net/98o7m7am/

.wrapper {
  width: 150px;
}
.table {
  display: table;
}
.table > div {
  display: table-cell;
}
.line {
  display: flex;
  width: 100%;
}
.line span:first-child {
  white-space: nowrap;
  flex-grow: 1;
  overflow: hidden;
  text-overflow: ellipsis;
}
.line span:last-child {
  flex-shrink: 0;
  margin-left: 5px;
}

<div class="wrapper">
  <div class="line">
    <span>Very long label text</span>
    <span>12345</span>
  </div>
</div>
<div class="table wrapper">
  <div>
    <div class="line">
      <span>Very long label text</span>
      <span>12345</span>
    </div>
  </div>
</div>

Update: I ended up 'solving' this by using more flexboxes instead of tables, but I would still like to know why the original example doesn't work.

Answer 1

That's because, by default, tables use the automatic table layout:

The CSS 2.1 spec doesn't define that layout mode, but suggests a (non-normative) algorithm, which reflects the behavior of several popular HTML user agents.

According to that algorithm, the table's width will only be treated like a minimum width, and the real width will be enough so that the content does not overflow:

Calculate the minimum content width (MCW) of each cell: the formatted content may span any number of lines but may not overflow the cell box.

Since you have white-space: nowrap, the MCW will be the width of the full text.

To avoid that, you can set the initial width of your first span to 0:

.line span:first-child {
  width: 0;
}

.wrapper {
  width: 150px;
}
.table {
  display: table;
}
.table > div {
  display: table-cell;
}
.line {
  display: flex;
  width: 100%;
}
.line span:first-child {
  width: 0;
  white-space: nowrap;
  flex-grow: 1;
  overflow: hidden;
  text-overflow: ellipsis;
}
.line span:last-child {
  flex-shrink: 0;
  margin-left: 5px;
}

<div class="wrapper">
  <div class="line">
    <span>Very long label text</span>
    <span>12345</span>
  </div>
</div>
<div class="table wrapper">
  <div>
    <div class="line">
      <span>Very long label text</span>
      <span>12345</span>
    </div>
  </div>
</div>

Alternatively, you may want to try the fixed table mode, which is properly defined in the spec (and thus more reliable), is usually faster, and solves the problem too.

table-layout: fixed;

.wrapper {
  width: 150px;
}
.table {
  display: table;
  table-layout: fixed;
}
.table > div {
  display: table-cell;
}
.line {
  display: flex;
  width: 100%;
}
.line span:first-child {
  white-space: nowrap;
  flex-grow: 1;
  overflow: hidden;
  text-overflow: ellipsis;
}
.line span:last-child {
  flex-shrink: 0;
  margin-left: 5px;
}

<div class="wrapper">
  <div class="line">
    <span>Very long label text</span>
    <span>12345</span>
  </div>
</div>
<div class="table wrapper">
  <div>
    <div class="line">
      <span>Very long label text</span>
      <span>12345</span>
    </div>
  </div>
</div>