前端分页处理

页面中实现的分页效果，要么后端提供接口，每次点击下一页就调用接口，若不提供接口，分页得前端自己去截取。

方法一：slice方法
slice(参数1，参数2)方法是返回一个新的数组对象，左开右闭
参数1：起始下标数
参数2：结束下标数(不计算在内)
如data:[1,2,3,4,5,6,7,8]，那么data.slice(0,3)就为下标为0，1，2,不包括下标为3的数，即[1,2,3]，可以看成数学中的[0,3)

slice方法详细讲解

这个原理就和分页原理很相似，分页也是把一个很长的数组，按照每页多少条（size）分为若干个短数组

//allData为全部数据，tableData是目前表格绑定的数据
(this.page - 1) * this.size,
this.page * this.size
);
this.total=this.allData.length

下面是详细代码：

比如：data=[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19]
总条目数total=20，
若设size=3（每页3条）

方法二：splice方法
splice方法可以理解为删除，与方法一的slice只差一个p字母
用splice分页，需要用到的有2个参数，
splice(参数1，参数2)
参数1：从第几位开始
参数2：删除几个元素
如data:[1,2,3,4,5,6,7,8]，那么data.splice(0,3)就是从第0位开始，删除3个元素，即删除的元素为[1,2,3]，剩余元素为data:[4,5,6,7,8]，此方法会改变原数组

splice方法详细讲解

这个原理要和分页原理结合关联起来，如果一页3条数据，第一页就是从0位开始，删除的3个元素，即splice(0,3)，第二页就是从第3位开始，删除的3个元素，即splice（3,3）
因此用splice分页的关键语句就是：

  let data=JSON.parse(JSON.stringify(this.allData))
   this.tableData = data.splice(
     (this.page - 1) * this.size,
     this.size
   );
   this.total=this.allData.length

注意:splice会改变原数组，因为它使用一次，相当于原数组就被删除了一些元素，必须使用深拷贝先拷贝一份allData，然后再取被删除的元素赋值给tableData 。

其余代码不变，只是略微改变处理完整数据的方法

比如：
data=[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19]
由于深拷贝的原因，data可以等于完整的allData，
总条目数total=20，
若设size=3（每页3条）

两种方法的总结

最后完整代码如下：

<template>
  <div>
    <el-table :data="tableData" border>
      <el-table-column label="序号" type="index" width="50">
      </el-table-column>
      <el-table-column prop="date" label="日期" width="180">
      </el-table-column>
      <el-table-column prop="name" label="姓名" width="180">
      </el-table-column>
      <el-table-column prop="address" label="地址">
      </el-table-column>
    </el-table>

    <el-pagination @size-change="sizeChange" @current-change="currentChange"
      :current-page="page" :page-size="size" :page-sizes="pageSizes"
      layout="total, sizes, prev, pager, next, jumper" :total="total">
    </el-pagination>
  </div>
</template>
<script>
export default {
  data() {
    return {
      page: 1, //第几页
      size: 3, //一页多少条
      total: 0, //总条目数
      pageSizes: [3, 5, 10, 20, 50, 100, 200, 300, 400, 500, 1000], //可选择的一页多少条
      tableData: [], //表格绑定的数据
      allData: [
        {
          date: "2016-05-02",
          name: "王小虎1",
          address: "上海市普陀区金沙江路 1518 弄",
        },
        {
          date: "2016-05-04",
          name: "王小虎2",
          address: "上海市普陀区金沙江路 1517 弄",
        },
        {
          date: "2016-05-01",
          name: "王小虎3",
          address: "上海市普陀区金沙江路 1519 弄",
        },
        {
          date: "2016-05-03",
          name: "王小虎4",
          address: "上海市普陀区金沙江路 1516 弄",
        },
        {
          date: "2016-05-02",
          name: "王小虎5",
          address: "上海市普陀区金沙江路 1518 弄",
        },
        {
          date: "2016-05-04",
          name: "王小虎6",
          address: "上海市普陀区金沙江路 1517 弄",
        },
        {
          date: "2016-05-01",
          name: "王小虎7",
          address: "上海市普陀区金沙江路 1519 弄",
        },
        {
          date: "2016-05-03",
          name: "王小虎8",
          address: "上海市普陀区金沙江路 1516 弄",
        },
        {
          date: "2016-05-02",
          name: "王小虎9",
          address: "上海市普陀区金沙江路 1518 弄",
        },
        {
          date: "2016-05-04",
          name: "王小虎10",
          address: "上海市普陀区金沙江路 1517 弄",
        },
        {
          date: "2016-05-01",
          name: "王小虎11",
          address: "上海市普陀区金沙江路 1519 弄",
        },
        {
          date: "2016-05-03",
          name: "王小虎12",
          address: "上海市普陀区金沙江路 1516 弄",
        },
        {
          date: "2016-05-02",
          name: "王小虎13",
          address: "上海市普陀区金沙江路 1518 弄",
        },
        {
          date: "2016-05-04",
          name: "王小虎14",
          address: "上海市普陀区金沙江路 1517 弄",
        },
        {
          date: "2016-05-01",
          name: "王小虎15",
          address: "上海市普陀区金沙江路 1519 弄",
        },
        {
          date: "2016-05-03",
          name: "王小虎16",
          address: "上海市普陀区金沙江路 1516 弄",
        },
        {
          date: "2016-05-02",
          name: "王小虎17",
          address: "上海市普陀区金沙江路 1518 弄",
        },
        {
          date: "2016-05-04",
          name: "王小虎18",
          address: "上海市普陀区金沙江路 1517 弄",
        },
        {
          date: "2016-05-01",
          name: "王小虎19",
          address: "上海市普陀区金沙江路 1519 弄",
        },
        {
          date: "2016-05-03",
          name: "王小虎20",
          address: "上海市普陀区金沙江路 1516 弄",
        },
        {
          date: "2016-05-02",
          name: "王小虎21",
          address: "上海市普陀区金沙江路 1518 弄",
        },
        {
          date: "2016-05-04",
          name: "王小虎22",
          address: "上海市普陀区金沙江路 1517 弄",
        },
        {
          date: "2016-05-01",
          name: "王小虎23",
          address: "上海市普陀区金沙江路 1519 弄",
        },
        {
          date: "2016-05-03",
          name: "王小虎24",
          address: "上海市普陀区金沙江路 1516 弄",
        },
        {
          date: "2016-05-02",
          name: "王小虎25",
          address: "上海市普陀区金沙江路 1518 弄",
        },
        {
          date: "2016-05-04",
          name: "王小虎26",
          address: "上海市普陀区金沙江路 1517 弄",
        },
        {
          date: "2016-05-01",
          name: "王小虎27",
          address: "上海市普陀区金沙江路 1519 弄",
        },
        {
          date: "2016-05-03",
          name: "王小虎28",
          address: "上海市普陀区金沙江路 1516 弄",
        },
        {
          date: "2016-05-02",
          name: "王小虎29",
          address: "上海市普陀区金沙江路 1518 弄",
        },
        {
          date: "2016-05-04",
          name: "王小虎30",
          address: "上海市普陀区金沙江路 1517 弄",
        },
        {
          date: "2016-05-01",
          name: "王小虎31",
          address: "上海市普陀区金沙江路 1519 弄",
        },
        {
          date: "2016-05-03",
          name: "王小虎32",
          address: "上海市普陀区金沙江路 1516 弄",
        },
        {
          date: "2016-05-02",
          name: "王小虎33",
          address: "上海市普陀区金沙江路 1518 弄",
        },
        {
          date: "2016-05-04",
          name: "王小虎34",
          address: "上海市普陀区金沙江路 1517 弄",
        },
        {
          date: "2016-05-01",
          name: "王小虎35",
          address: "上海市普陀区金沙江路 1519 弄",
        },
        {
          date: "2016-05-03",
          name: "王小虎36",
          address: "上海市普陀区金沙江路 1516 弄",
        },
        {
          date: "2016-05-02",
          name: "王小虎37",
          address: "上海市普陀区金沙江路 1518 弄",
        },
        {
          date: "2016-05-04",
          name: "王小虎38",
          address: "上海市普陀区金沙江路 1517 弄",
        },
        {
          date: "2016-05-01",
          name: "王小虎39",
          address: "上海市普陀区金沙江路 1519 弄",
        },
        {
          date: "2016-05-03",
          name: "王小虎40",
          address: "上海市普陀区金沙江路 1516 弄",
        },
        {
          date: "2016-05-02",
          name: "王小虎41",
          address: "上海市普陀区金沙江路 1518 弄",
        },
        {
          date: "2016-05-04",
          name: "王小虎42",
          address: "上海市普陀区金沙江路 1517 弄",
        },
        {
          date: "2016-05-01",
          name: "王小虎43",
          address: "上海市普陀区金沙江路 1519 弄",
        },
        {
          date: "2016-05-03",
          name: "王小虎44",
          address: "上海市普陀区金沙江路 1516 弄",
        },
        {
          date: "2016-05-02",
          name: "王小虎45",
          address: "上海市普陀区金沙江路 1518 弄",
        },
        {
          date: "2016-05-04",
          name: "王小虎46",
          address: "上海市普陀区金沙江路 1517 弄",
        },
        {
          date: "2016-05-01",
          name: "王小虎47",
          address: "上海市普陀区金沙江路 1519 弄",
        },
        {
          date: "2016-05-03",
          name: "王小虎48",
          address: "上海市普陀区金沙江路 1516 弄",
        },
        {
          date: "2016-05-02",
          name: "王小虎49",
          address: "上海市普陀区金沙江路 1518 弄",
        },
        {
          date: "2016-05-04",
          name: "王小虎50",
          address: "上海市普陀区金沙江路 1517 弄",
        },
        {
          date: "2016-05-01",
          name: "王小虎51",
          address: "上海市普陀区金沙江路 1519 弄",
        },
        {
          date: "2016-05-03",
          name: "王小虎52",
          address: "上海市普陀区金沙江路 1516 弄",
        },
      ],
    };
  },
  methods: {
      //获取表格数据，自行分页(slice)
    getTabelData() {
        //allData为全部数据
      this.tableData = this.allData.slice(
        (this.page - 1) * this.size,
        this.page * this.size
      );
      this.total=this.allData.length
    },

    //获取表格数据，自行分页（splice）
    getTabelData2() {
      let data=JSON.parse(JSON.stringify(this.allData))
      this.tableData = data.splice(
        (this.page - 1) * this.size,
        this.size
      );
      this.total=this.allData.length
    },
    //page改变时的回调函数，参数为当前页码
     currentChange(val) {
      console.log("翻页，当前为第几页", val);
      this.page = val;
      this.getTabelData2();
    },
    //size改变时回调的函数，参数为当前的size
    sizeChange(val) {
      console.log("改变每页多少条，当前一页多少条数据", val);
      this.size = val;
      this.page = 1; 
      this.getTabelData2();
    },
  },
  created() {
    this.getTabelData2();
  },
};
</script>