需求：左右两边是按钮或者图标，贴在边缘，中间是字符串加上一个label，label紧贴在字符串最后，如果中间区域太窄，label不变，过长的字符串自动显示为省略号 ...
实现
<!DOCTYPE html>
<html lang="zh-Hans">
<head>
<meta charset="UTF-8">
<title>HTML测试文档</title>
<style>
.item {
display: flex;
align-items: center;
width: 500px;
margin: 4px 0;
border: 1px solid red;
}
.item .severity-icon {
width: 7px;
height: 7px;
border-radius: 3.5px;
background-color: red;
flex: 0 0 7px;
}
.item h4 {
display: flex;
align-items: center;
flex: 1 1 auto; /*关键点一*/
margin: 0 5px;
width: 80%; /*关键点二，这个值一定要比它实际占用的宽度小，如果设置为100%，就会超出item这个框*/
border: 1px solid blue;
}
.item h4 span {
overflow: hidden;
margin-right: 4px;
font-size: 12px;
white-space: nowrap;
text-overflow: ellipsis;
}
.item h4 i {
flex: 0 0 auto;
padding: 2px 4px;
font-size: 10px;
color: #fff;
font-weight: normal;
font-style: normal;
background-color: #1d1d1d;
}
.item .btn-remove {
flex: 0 0 16px;
padding: 0 4px;
cursor: pointer;
text-align: center;
font-style: normal;
vertical-align: middle;
background-color: gray;
}
</style>
</head>
<body>
<div class="item">
<i class="severity-icon"></i>
<h4>
<span>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Lorem ipsum dolor sit amet, consectetuer adipiscing elit.</span>
<i>Node.js</i>
</h4>
<i class="btn-remove">✕</i>
</div>
</body>
</html>