js获取.号前面的字符串

       <el-tab-pane
          :label="item.contractName"
          v-for="item in items"
          :key="item.id"
          :name="item.id"
          >{{ item.contractName }}
        </el-tab-pane>

 

items: [
        {
          id: 1,
          contractName: '离职证明.pdf',
        },
        {
          id: 2,
          contractName: '员工入职手册.pdf',
        },
      ],



nameCc() {
      for (let i = 0; i < this.items.length; i++) {
        let cc = this.items[i].contractName.indexOf('.');
        console.log(cc);
       this.items[i].contractName = this.items[i].contractName.slice(0, cc);
      }
    },