es6 循环 过滤 取值

关于es6一些应用 和 其他对前后台数据的处理

---

一、给数组里的对象添加一个属性

this.data.forEach((item,index)=>{
   needData.push(
       Object.assign({},item,
           {'addAttr':'addAttrContent'})
   )
})

二、下拉选择得到id 获取其他属性

 let currentItemSkuUnit = {};
  currentItemSkuUnit = this.specKeyData.find((item) => {
     return item.id === value;
  });
  this.detailForm.specRatio = currentItemSkuUnit.specRatio;

三、属性替换

 this.addFormDataOne = JSON.parse(JSON.stringify(this.addFormDataOne).replace(/cusAddress/g, 'address'))

四、遍历数组为【1，2，3，4】

 this.detailForm.areas = [];
 this.categoryData.map((item) => {
    this.detailForm.areas.push(item.whAId);
  });

五、根据条件过滤数组

this.detailForm.owners = this.detailForm.owners.filter((item) => {
       return item !== "null";
 });

六、树形结构设置disabled属性

tickMenuIdFilter(arr, data) {
      var newArr = [];
      if (arr != undefined && arr.length > 0) {
        newArr = arr.map((item) => {
          item.disabled = data;
          if (item.areaList != undefined && item.areaList.length > 0) {
            this.tickMenuIdFilter(item.areaList, data);
          }
          return item;
        });
      }
      console.log(newArr);
      return newArr;
    },
 
this.tickMenuIdFilter(this.popupTreeData, true)

七、遍历数组 修改属性值

 		  data.forEach((item) => {
          if (item.whState == 0) {
            item.whState = false;
          } else {
            item.whState = true;
          }
          return data;
        });
        this.popupTreeData = data;

八、遍历数组 添加属性值

		var arr = [];
        this.adjustType.forEach((item, index) => {
          if (item.id !== row.state) {
            arr.push(Object.assign({}, item, { disabled: true }));
            this.adjustType = arr;
          }
        });

九、数组A有数组B的数据就删除

	  arrayWeightRemoval(array1, array2) {
      //临时数组存放
      var tempArray1 = []; //临时数组1
      var tempArray2 = []; //临时数组2
      for (var i = 0; i < array2.length; i++) {
        tempArray1[array2[i]] = true; //将数array2 中的元素值作为tempArray1 中的键，值为true；
      }
      for (var i = 0; i < array1.length; i++) {
        if (!tempArray1[array1[i]]) {
          tempArray2.push(array1[i]); //过滤array1 中与array2 相同的元素；
        }
      }
      return tempArray2;
    }

十、es6 两个数组取相同项和不同项

//相同
let arr = [{ id: 1, name: 'zs' }, { id: 2, name: 'ls' }, { id: 3, name: 'ww' }, { id: 4, name: 'xm' }, { id: 5, name: 'xh' },]
let sum = [3, 4, 5]
let date = arr.filter(item => sum.indexOf(item.id) > -1)
console.log('date', date)
// 0: {id: 3, name: "ww"}
// 1: {id: 4, name: "xm"}
// 2: {id: 5, name: "xh"}
//相同
let arr = [{ id: 1, name: 'zs' }, { id: 2, name: 'ls' }, { id: 3, name: 'ww' }, { id: 4, name: 'xm' }, { id: 5, name: 'xh' },]
let arr2 = [{ id: 1, name: 'zs' }]
let newArr = arr.filter((item) =>
              arr2.some((ele) => ele.id === item.id)
            );
console.log('newArr', newArr )
//不同
let arr = [{ id: 1, name: 'zs' }, { id: 2, name: 'ls' }, { id: 3, name: 'ww' }, { id: 4, name: 'xm' }, { id: 5, name: 'xh' },]
let arr2 = [{ id: 1, name: 'zs' }]
let newArr = arr.filter((item) =>
              !arr2.some((ele) => ele.id === item.id)
            );
console.log('newArr', newArr )

十一、实现从json中取值并返回新的数组或者字符串

data:[
  {
    'Id': '1',
    'Phone': '123456',
    'Name': '张三',
  },
  {
    'Id': '2',
    'Phone': '78945',
    'Name': '李四',
  },
  {
    'Id': '3',
    'Phone': '123789',
    'Name': '王五',
  }
]
//data json的名称,n是自定义取的
let result = data.map(n=> n.name).join();//'张三,李四,王五'

let results = data.map(n => n.name);//['张三','李四','王五']

十二、删除对象或数组中的某个属性

1.删除对象中的某个属性

let { createTime, ...params } = data;
 console.log(params)
 最后这个params就是我们需要的值

2.删除数组中的某个属性

  var arrayData = [
      {
        index: 0,
        is_required: true,
        name: "vmvdnksl",
        type: "LONG_TEXT",
      },
      {
        index: 1,
        is_required: true,
        name: "dsvnlk",
        type: "MULTIPLE_SELECTORS",
      },
    ];

    for (let key in arrayData) {
      delete arrayData[key].index;
    }
    ```
# 十三、过滤组数中null 空字符串 undefined

```javascript

var arr = ['1','2',undefined, '3.jpg',undefined]
var newArr = arr.filter(item => item)
console.log(newArr)
 
var arr = ['1','2',null, '3.jpg',null]
var newArr = arr.filter(item => item)
console.log(newArr)
 
>//空字符串里面不能包含空格
var arr = ['1','2','', '3.jpg','']
var newArr = arr.filter(item => item)
console.log(newArr)

十四、大小写转换

  // 大写转换
        function upperJSONKey(jsonObj){
            for (var key in jsonObj){
                jsonObj["\""+key.toUpperCase()+"\""] = jsonObj[key];
                delete(jsonObj[key]);
            }
            return jsonObj;
        }
 
        // 小写转换
        function lowerJSONKey(jsonObj){
            for (var key in jsonObj){
                jsonObj["\""+key.toLowerCase()+"\""] = jsonObj[key];
                delete(jsonObj[key]);
            }
            return jsonObj;
        }
 
        var obj = {KEY:'value'};
        var newObj = lowerJSONKey(obj);
        console.log(newObj);

十五、对象数组去重

const arr = [
        {
          name: '张三',
          age: 22
        },
        {
          name: '李四',
          age: 22
        },
        {
          name: '张三',
          age: 23
        }
      ]
      const map = new Map()
      const qc = arr.filter(key => !map.has(key.name) && map.set(key.name, 1)) // 这里对name属性进行去重
      console.log('qc')
      console.log(qc)

十六、数组里某个字段排顺序

   var detailsData = res.data.data.details;
          detailsData.sort((old, New) => {
            return old.diffNum - New.diffNum;
          });

十七、数组里的数组添加新属性

   this.detailList = res.data.data;
   this.detailList.forEach((item, index) => {
            if (item.allocateResult) {
              var ResultData = [];
              item.allocateResult.forEach((key) => {
                ResultData.push(
                  Object.assign(key, {
                    inventoryOutStateTwo: item.inventoryOutState,
                  })
                );
              });
              item.allocateResult = ResultData;
              console.log(item.allocateResult);

十八、解析headers里content-disposition文件名称

        let filename = decodeURIComponent(
          res.headers["content-disposition"].split("filename=")[1]
        );
        link.setAttribute("download", filename);

十九、查找选中数值下标

 changeZcodeEnd(value) {
  const ZcodeData = ['a','b','c'];
  const One = ZcodeData.findIndex((item) => {
       return item == value;
  });
  console.log(One)
 }

二十、es6两个数组比较如果某字段相同，给一个字段赋值

     this.tableHeadsSon.filter((item) => {
          tableHeadsData.find((key) => {
            if (item.prop == key.prop) {
              return (item.width = key.width);
            }
          });
        });

二十一、数组里的字符串数字与数字互转

var arr = [1, 2, 3, 4, 5];
arr.map(String);  // ['1', '2', '3', '4', '5']

var arr2 = ['1', '2', '3', '4', '5']
arr2.map(Number);  //[1, 2, 3, 4, 5]

二十二、350000转成350，000

 new Intl.NumberFormat().format(350000)

二十三、数据转为以万为单位

//转换单位万
export function formatNumber(num) {
 num = Number(num);
 if (num == 0) {
  return num + '';
 } else if (num > 0 && num < 10000) {
  return parseFloat((num).toFixed(2)) + '';
 } else {
  return (num / 10000).toFixed(2) + '万';
 }
}

二十四、需要用A接口得参数去请求B接口

Promise.all([
      new Promise((resolve, reject) => {
        //请求A接口，这里用setTimeout模拟请求
        setTimeout(() => {
          resolve("A的结果");
        }, 2000);
      }),
      new Promise((resolve, reject) => {
        //请求B接口，这里用setTimeout模拟请求
        setTimeout(() => {
          resolve("B的结果");
        }, 1000);
      }),
    ])
      .then((res) => {
        console.log(res[0]); //A的结果
        console.log(res[1]); //B的结果
        //根据A和B的结果请求C接口数据
        setTimeout(() => {
          console.log("C的请求结果");
        }, 100);
      })
      .catch((err) => {
        console.log(err);
      });

二十五、es6去重

const arr = [
        {
          name: '张三',
          age: 22
        },
        {
          name: '李四',
          age: 22
        },
        {
          name: '张三',
          age: 23
        }
      ]
let results = arr .map(n => n.name);
let narr1 = [...new Set(results)]

二十五、es6去数组中的值作为对象里的键

const arr = [{date: "2018-11-18", name: "demo1"}, {date: "2018-11-19", name: "demo2"}];
      const target = {};
      arr.forEach(a => {
        const source = JSON.parse(`{"${a.date}":"${a.name}"}`);//利用JSON.parse将对象
                                                              //格式直接造出来
        Object.assign(target,source);
      })
     // console.log(target)
    //  target = {
	//"2018-11-18":"demo1",
	//"2018-11-19":"demo2"
}