this.$set的正确使用

this.tableData.forEach((item, index) => {
                let ZKprice = (item.price * this.discount * 0.1).toFixed(2);
// 要修改的数据 索引 要改的值 三个参数
                this.$set(this.tableData, index, { ZKprice: ZKprice, SetPrice: this.discount, limit_stock: item.limit_stock });
            });

 

textJsona: function () {
            let vm = this
            let textJson300 = [
                {t1: 't1',t2: 't2',t3: 't3'},
                {t4: 't4',t5: 't5',t6: 't6'},
                {t7: 't7',t8: 't8',t9: 't9'},
            ]
          vm.$set(vm.textJson[1],'t5',textJson300[1].t5) 
            //此时等效于 vm.$set(vm,'textJson',textJson300)
        }