实现效果：

template：

          <!--产品白名单-->
          <div class="con-item" v-if="current == 0">

            <el-form-item label="平台名称">

              <div class="contaion" @click="onclick">

                <!-- 生成的标签 -->
                <div v-for="(item, index) in uniqueArray" :key="index" class="spanbox">
                  <span class="tagspan">{{ item }}</span>
                  <i class="iClose" @click="removeTag(item,index)"></i>
                </div>
                <!-- 输入框 -->
                <input
                  v-model="inputValue"
                  :style="inputStyle"
                  class="inputTag"
                  ref="inputTag"
                  type="text"
                />

              </div>

            </el-form-item>

            <el-table v-loading="loading" :data="dialogWhitelist" @selection-change="handleSelectionChange">
              <el-table-column label="ID" align="center" prop="id" />
              <el-table-column label="平台名称" align="center" prop="platformName" />
              <el-table-column label="展业模式" align="center" prop="promoteMode" />
              <el-table-column label="产品" align="center" prop="productName" />
              <el-table-column type="selection" width="55" align="center" />
            </el-table>  
          </div>

主要是这一块代码：

v-for 遍历 uniqueArray数组 显示一个个tag，每一个tag后面有一个清除图标和removeTag事件。

              <div class="contaion" @click="onclick">

                <!-- 生成的标签 -->
                <div v-for="(item, index) in uniqueArray" :key="index" class="spanbox">
                  <span class="tagspan">{{ item }}</span>
                  <i class="iClose" @click="removeTag(item,index)"></i>
                </div>
                <!-- 输入框 -->
                <input
                  v-model="inputValue"
                  :style="inputStyle"
                  class="inputTag"
                  ref="inputTag"
                  type="text"
                />

              </div>

script

const deepTagsAll = ref([]);//没有去重的数组
const inputValue = ref("");

  //点击叉叉删除tag
function removeTag(item,index) {
  this.deepTagsAll.splice(index, 1);
}

watch(//监听input框长度
  () => inputValue.value.length,
  (newLength, oldLength) => {
    console.log(`Input length changed from ${oldLength} to ${newLength}`);
    // 这里可以根据长度变化执行相应的逻辑
    // 实时改变input输入框宽度，防止输入内容超出input默认宽度显示不全
    inputLength = $refs.inputTag.value.length * 12 + 50;
  }
);

//计算属性 去重复
const uniqueArray = computed(() => [...new Set(deepTagsAll.value)]);

/** 产品白名单多选框选中数据 */
function handleSelectionChange(selection) {
  var newArr=Array.from(selection);
  for (let i = 0; i < newArr.length; i++) {
    const newRow = {
      businesId: newArr[i].id,
      platformName: newArr[i].platformName,
      exhibitionMode: newArr[i].promoteMode,
      productName: newArr[i].productName
  }
  selectWhitelist.value.push(newRow)// 往list中放一个空对象
  //添加tag
  deepTagsAll.value.push(newArr[i].platformName)
  }

把每一个勾选的值放到deepTagsAll数组里面，由于可能出现选完了再选一次的情况，所以添加一个computed 给数组去重复放到uniqueArray 数组里面

style

<style  scoped>
  .contaion {
  width: 600px;
  box-sizing: border-box;
  background-color: white;
  border: 1px solid #409EFF;
  border-radius: 4px;
  font-size: 12px;
  text-align: left;
  padding-left: 5px;
  word-wrap: break-word;
  overflow: hidden;
  }
  /* 标签 */
  .spanbox {
  display: inline-block;
  font-size: 14px;
  margin: 3px 4px 3px 0;
  background-color: #ecf5ff;
  border: 1px solid #e8eaec;
  border-radius: 3px;
  box-shadow: 0 2px 4px rgba(0, 0, 0, .12), 0 0 6px rgba(0, 0, 0, .04)
  }
  /* 标签文字 */
  .tagspan {
  height: 24px;
  line-height: 22px;
  max-width: 99%;
  position: relative;
  display: inline-block;
  padding-left: 8px;
  color: #409EFF;
  font-size: 14px;
  opacity: 1;
  vertical-align: middle;
  overflow: hidden;
  transition: 0.25s linear;
  }
  /* tag的叉叉 */
  .iClose {
  padding: 0 6px 0 4px;
  opacity: 1;
  -webkit-filter: none;
  filter: none;
  color: #409EFF;
  /* font-weight: 600; */
  cursor:pointer;
  }
  /* 鼠标经过叉叉 */
  .iClose:hover{
  background-color: #409EFF;
  border-radius: 50%;
  color: #fff;
  }
  .iClose:after {
  content: "\00D7";
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  /* line-height: 27px; */
  transition: 0.3s, color 0s;
  }
  /* input */
  .inputTag {
  font-size: 16px;
  border: none;
  box-shadow: none;
  outline: none;
  background-color: transparent;
  padding: 0;
  width: auto;
  min-width: 150px;
  vertical-align: top;
  height: 32px;
  color: #495060;
  line-height: 32px;
  }
  /* 输入框提示文字大小 */
  input:placeholder-shown {
  font-size: 10px;
  }

</style>

这块存放tag的是一个虚拟的边框，所以.contaion这个样式不能丢。