Word-wrap doesn't respect parent's width for long non-break text

Question

.container {
  /* 
     Container's width can be dynamically resized. 
     I put width = 300px in the example to demonstrate a case 
     where container's width couldn't hold second msg 
  */
  width: 300px;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  padding: 1em;
  background-color: blue;
}

.parent{
  display:flex;
  flex-direction:row;
  flex-wrap:nowrap;
  padding:1em;
  background-color:red;
  box-sizing:border-box;
  margin-bottom: 1em;
}
.name{
  background-color:mistyrose;
  width: 70px;
  padding: 1em;
}
.msg{
  background-color:powderblue;
  max-width: 30vw;
  padding:.5em;
  word-wrap:break-word;
}

<div class='container'>
 <div class="parent">
    <div class="name">
      David
    </div>
    <div class="msg">
    How are you? How are you? How are you? How are you? How are you? How are you? How are you? How are you? How are you? How are you? How are you? How are you? How are you? 

    </div>
  </div>
  <div class="parent">
    <div class="name">
      Hannah
    </div>
    <div class="msg">
    somethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomething

    </div>
  </div>
</div>

Ideally , I want each msg to have max-width of 30vw, but at the same time respect parent's width. The first row behaves correctly, but the second row doesn't. If parent's width is resized to some value smaller than 30vw, the second msg will overflow.

I want something like max-width = min(30vw, parent's width)

NOTE: Container's width can be dynamically resized. I put width = 300px in the example to demonstrate a case where container cannot hold the second msg which somehow has width = it's max-width = 30vw.

You can also see the example at http://jsfiddle.net/vbj10x4k/231/

Answer 1

Simply set max-width:100% to .parent so this one respect the width of .container then rely on flex and your element will shrink by default. Also don't forget min-width:0 on the element itself to enable the element to shrink.

.container {
  width: 300px;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  padding: 1em;
  background-color: blue;
}

.parent{
  display:flex;
  flex-direction:row;
  flex-wrap:nowrap;
  padding:1em;
  background-color:red;
  box-sizing:border-box;
  margin-bottom: 1em;
  max-width:100%; /*Added this */
}
.name{
  background-color:mistyrose;
  width: 70px;
  padding: 1em;
}
.msg{
  background-color:powderblue;
  max-width:30vw;
  min-width:0; /*addedd this*/
  padding:.5em;
  word-wrap:break-word;
}

<div class='container'>
 <div class="parent">
    <div class="name">
      David
    </div>
    <div class="msg">
    How are you? How are you? How are you? How are you? How are you? How are you? How are you? How are you? How are you? How are you? How are you? How are you? How are you? 

    </div>
  </div>
  <div class="parent">
    <div class="name">
      Hannah
    </div>
    <div class="msg">
    somethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomethingsomething

    </div>
  </div>
</div>

Answer 2

If you do not need to support IE11 or safari, a simple solution would be to switch your word-wrap:break-word; with word-wrap: anywhere (working example)

If you need to support safari (but still not IE11), then instead replace word-wrap:break-word; with word-break: break-word. Note that word-break: break-word is deprecated in favour of word-wrap: anywhere.

I would also recommend switching word-wrap for its more commonly used alias: overflow-wrap. It will be more effective when used in a search term.

Also see: Difference between overflow-wrap and word-break?