html - 父 flexbox 容器忽略子 flexbox 的最小宽度

Question

很短的史前史

我的故事始于努力让 overflow-wrap: break-word; 在 flexbox 中工作。 Flexbox 容器不想理解它的元素可以收缩，尽管元素可以打断长词:

.body {
  width: 300px;
  border: 1px solid black;
  padding: 8px;
  background-color: #ccc;
}

.flex-column {
  display: flex;
}

.item {
  overflow-wrap: break-word;
  background-color: #fff;
  padding: 8px;
}

<div class="body">
  <div class="flex-column">
    <div class="item">
      This is Spaaaaaaaaaaaaaaaarrrrrrrrrrrrrttttttttttttttaaaaaaaaaaaaaaaaaaaaaa!11 It's not a bug. Firefox is correctly implementing min-width: auto for flex items. When you change it to min-width: 0, you're just using a different value for min-width to get your example looking how you want it to look. But both values are being rendered correctly.
    </div>
  </div>
</div>

幸运的是，我们可以帮助 flexbox 理解它可以在元素上使用 min-width: 0; 来缩小它的元素:

.body {
  width: 300px;
  border: 1px solid black;
  padding: 8px;
  background-color: #ccc;
}

.flex-column {
  display: flex;
}

.item {
  overflow-wrap: break-word;
  background-color: #fff;
  padding: 8px;
  /* Okay, it fixes this */
  min-width: 0;
}

<div class="body">
  <div class="flex-column">
    <div class="item">
      This is Spaaaaaaaaaaaaaaaarrrrrrrrrrrrrttttttttttttttaaaaaaaaaaaaaaaaaaaaaa!11 It's not a bug. Firefox is correctly implementing min-width: auto for flex items. When you change it to min-width: 0, you're just using a different value for min-width to get your example looking how you want it to look. But both values are being rendered correctly.
    </div>
  </div>
</div>

然而，现实世界有点复杂。

问题

在我们的应用程序中，我们有许多嵌套的 flexbox 。所以这个例子应该是这样的:

.body {
  width: 300px;
  border: 1px solid black;
  padding: 8px;
  background-color: #ccc;
}

.flex {
  display: flex;
}

.flex-column {
  display: flex;
}

.item {
  min-width: 0;
  padding: 8px;
  background-color: #fff;
  overflow-wrap: break-word;
}

<div class="body">
  <div class="flex">
    <div class="flex">
      <div class="flex">
        <div class="flex-column">
            <div class="item">
              This is Spaaaaaaaaaaaaaaaarrrrrrrrrrrrrttttttttttttttaaaaaaaaaaaaaaaaaaaaaa!11 It's not a bug. Firefox is correctly implementing min-width: auto for flex items. When you change it to min-width: 0, you're just using a different value for min-width to get your example looking how you want it to look. But both values are being rendered correctly.
            </div>
          </div>
        </div>
      </div>
    </div>
  </div>
</div>

如您所见，我们的 flex-column 的 flex 容器忽略了一个事实，即它的子项可以很好地收缩。我不明白为什么它会这样。你能给我解释一下吗？为什么 flexbox-container 不尊重它的子 flexbox min-width: 0？

我找到的解决方案是将 min-width: 0 设置为层次结构中的 all flexboxes，这看起来非常 hacky 和危险，因为我可以破坏我们的应用程序在意想不到的地方布局。

Answer 1

要理解这一点，只需为您的元素添加不同颜色的边框，您就会看到不同层次的溢出。更准确地说，我们只有一个溢出，在添加每个 min-width 后移动到较低的杠杆。

.body {
  width: 300px;
  border: 1px solid black;
  padding: 8px;
  background-color: #ccc;
}

.flex {
  display: flex;
}

.flex-column {
  display: flex;
}

.item {
  padding: 8px;
  background-color: #fff;
  overflow-wrap: break-word;
}

<div class="body">
  <div class="flex" style="border:5px solid red;">
    <div class="flex" style="border:5px solid green;">
      <div class="flex" style="border:5px solid blue;">
        <div class="flex-column" style="border:5px solid yellow;">
          <div class="item" style="border:5px solid pink;">
            This is Spaaaaaaaaaaaaaaaarrrrrrrrrrrrrttttttttttttttaaaaaaaaaaaaaaaaaaaaaa!11 It's not a bug. Firefox is correctly implementing min-width: auto for flex items. When you change it to min-width: 0, you're just using a different value for min-width to get
            your example looking how you want it to look. But both values are being rendered correctly.
          </div>
        </div>
      </div>
    </div>
  </div>
</div>

每个 min-width 都会修复一个溢出，允许元素收缩并将溢出移动到下一层。这就是为什么您需要级联 min-width。

添加一个:

.body {
  width: 300px;
  border: 1px solid black;
  padding: 8px;
  background-color: #ccc;
}

.flex {
  display: flex;
}

.flex-column {
  display: flex;
}

.item {
  padding: 8px;
  background-color: #fff;
  overflow-wrap: break-word;
}

<div class="body">
  <div class="flex" style="border:5px solid red;">
   <!-- adding min-width at this level -->
    <div class="flex" style="border:5px solid green;min-width:0;">
      <div class="flex" style="border:5px solid blue;">
        <div class="flex-column" style="border:5px solid yellow;">
            <div class="item" style="border:5px solid pink;">
              This is Spaaaaaaaaaaaaaaaarrrrrrrrrrrrrttttttttttttttaaaaaaaaaaaaaaaaaaaaaa!11 It's not a bug. Firefox is correctly implementing min-width: auto for flex items. When you change it to min-width: 0, you're just using a different value for min-width to get your example looking how you want it to look. But both values are being rendered correctly.
            </div>
          </div>
        </div>
      </div>
    </div>
  </div>
</div>

添加另一个:

.body {
  width: 300px;
  border: 1px solid black;
  padding: 8px;
  background-color: #ccc;
}

.flex {
  display: flex;
}

.flex-column {
  display: flex;
}

.item {
  padding: 8px;
  background-color: #fff;
  overflow-wrap: break-word;
}

<div class="body">
  <div class="flex" style="border:5px solid red;">
    <div class="flex" style="border:5px solid green;min-width:0;">
      <!-- adding min-width at this level -->
      <div class="flex" style="border:5px solid blue;min-width:0">
        <div class="flex-column" style="border:5px solid yellow;">
          <div class="item" style="border:5px solid pink;">
            This is Spaaaaaaaaaaaaaaaarrrrrrrrrrrrrttttttttttttttaaaaaaaaaaaaaaaaaaaaaa!11 It's not a bug. Firefox is correctly implementing min-width: auto for flex items. When you change it to min-width: 0, you're just using a different value for min-width to get
            your example looking how you want it to look. But both values are being rendered correctly.
          </div>
        </div>
      </div>
    </div>
  </div>
</div>

再次:

.body {
  width: 300px;
  border: 1px solid black;
  padding: 8px;
  background-color: #ccc;
}

.flex {
  display: flex;
}

.flex-column {
  display: flex;
}

.item {
  padding: 8px;
  background-color: #fff;
  overflow-wrap: break-word;
}

<div class="body">
  <div class="flex" style="border:5px solid red;">
    <div class="flex" style="border:5px solid green;min-width:0;">
      <div class="flex" style="border:5px solid blue;min-width:0">
       <!-- adding min-width at this level -->
        <div class="flex-column" style="border:5px solid yellow;min-width:0;">
          <div class="item" style="border:5px solid pink;">
            This is Spaaaaaaaaaaaaaaaarrrrrrrrrrrrrttttttttttttttaaaaaaaaaaaaaaaaaaaaaa!11 It's not a bug. Firefox is correctly implementing min-width: auto for flex items. When you change it to min-width: 0, you're just using a different value for min-width to get
            your example looking how you want it to look. But both values are being rendered correctly.
          </div>
        </div>
      </div>
    </div>
  </div>
</div>

最后一个:

.body {
  width: 300px;
  border: 1px solid black;
  padding: 8px;
  background-color: #ccc;
}

.flex {
  display: flex;
}

.flex-column {
  display: flex;
}

.item {
  padding: 8px;
  background-color: #fff;
  overflow-wrap: break-word;
}

<div class="body">
  <div class="flex" style="border:5px solid red;">
    <div class="flex" style="border:5px solid green;min-width:0;">
      <div class="flex" style="border:5px solid blue;min-width:0">
        <div class="flex-column" style="border:5px solid yellow;min-width:0;">
         <!-- adding min-width at this level -->
          <div class="item" style="border:5px solid pink;min-width:0">
            This is Spaaaaaaaaaaaaaaaarrrrrrrrrrrrrttttttttttttttaaaaaaaaaaaaaaaaaaaaaa!11 It's not a bug. Firefox is correctly implementing min-width: auto for flex items. When you change it to min-width: 0, you're just using a different value for min-width to get
            your example looking how you want it to look. But both values are being rendered correctly.
          </div>
        </div>
      </div>
    </div>
  </div>
</div>