一、獲取children數組長度
getMaxFloor (treeData) { //獲取樹長度
let max = 0
function each (data) {
for(let i = 0;i<data.length;i++){
max++;
if(data[i].children){
each(data[i].children);
}
}
}
each(treeData);
return max
},
二、查找數組對象的屬性是否有重複值
attrOnly(array, attr){
var first;
if(array.length>0){
for(let i=0;i<array.length;i++){
if(array[i][attr]!=""){
first = array[i][attr];
}
}
let num=0
for(let i=0;i<array.length;i++){
if(array[i][attr]==first){
num+=1
}
}
if(num>1){
return true
}else{
return false
}
}
},
//使用
attrOnly("要檢測的數組","要查的對應的屬性名稱")
attrOnly(arr,"name")
arr=[{"name","張三"},{"age",20}]
三、elemenyui表格的自定義順序,原理字符串的剪切替換
todown(index){//自定義順序
if(this.maketableData[0].children.length<2){
return;
}
let old_ = this.maketableData[0].children[index-1] //本行數據
let new_ = this.maketableData[0].children[index] //下一行的數據
let tableData_ = JSON.parse(JSON.stringify(this.maketableData));
tableData_[0].children.splice(index,1,old_)
tableData_[0].children.splice(index-1,1,new_)
this.maketableData = tableData_;
},
toup(index){
if(this.maketableData[0].children.length<2){
return;
}
let old_ = this.maketableData[0].children[index-1] //本行數據
let new_ = this.maketableData[0].children[index-2] //上一行的數據
let tableData_ = JSON.parse(JSON.stringify(this.maketableData));
tableData_[0].children.splice(index-2,1,old_)
tableData_[0].children.splice(index-1,1,new_)
this.maketableData = tableData_;
},
四、根據json數組的屬性值排序
creatCompare(propertyName) {
return function (obj1,obj2) {
var value1=obj1[propertyName];
var value2=obj2[propertyName];
if(value1<value2){
return -1
}else if(value1>value2){
return 1
}else {
return 0
}
}
},
使用:
var data=[{name:"xiaoming",age:13,weight:20,},{name:"liming",age:23,weight:21},{name:"zhangming",age:8,weight:66}]
console.log(data.sort(creatCompare("age")))
五、獲取當前時間戳
let timestamp = Date.parse(new Date());
this.mouthvalue = this.base.format(new Date(timestamp),"yyyy-MM")
六、根據時間獲得時間戳
let endDateVal = 2019-07-12 09:02:01
new Date(endDateVal).getTime()
七、數組從大到小排列
arr.sort(function(a,b){
return a>b;
//return a<b;//可試試這種的結果。
})
八、取數組中,每個元素的重複次數
//取重複數
arr = arr.sort()//先排序
function reactnum(arr){
let newArr = [];
for (let i = 0; i < arr.length;) {
let count = 0;
for (let j = i; j < arr.length; j++) {
if (arr[i] == arr[j]) {
count++;
}
}
newArr.push({
'Number': arr[i],
'count':count
});
i += count
}
return newArr
}
九、數組去重
function dedupe(array) {
return Array.from(new Set(array));
}
var arr = dedupe(arr)
十、普通數據轉爲樹數據(遞歸)
var data = [{id:1,parentId:0,name:"一"},{id:2,parentId:1,name:"二"},{id:3,parentId:2,name:"三"},{id:4,parentId:0,name:"四"}]
arrToTreeData(data,0)
function arrToTreeData(data, pId) {
let arr = [];
for (var i in data) {
if (data[i].parentId == pId) {
let item = data[i]
item.children = arrToTreeData(data, data[i].id);
arr.push(item);
}
}
return arr;
}
十一、獲取前幾個月的時間
getxData() {
let timex = [];
let newtime = new Date().getTime();
let newyear = this.$base.format(new Date(newtime), "yyyy");
let lastyear = newyear - 1;
let yearx = [String(lastyear), newyear];
let newmouth = this.$base.format(new Date(newtime), "MM");
let mouthx = [];
for (let i = 0; i < 5; i++) {
let item = new Date().setMonth(new Date().getMonth() - (4 - i));
mouthx.push(this.getMouth_(this.$base.format(new Date(item), "MM")));
}
let weekx = [];
for (let i = 0; i < 5; i++) {
let item = new Date().getTime() - 7 * (4 - i) * 3600 * 24 * 1000;
weekx.push(
this.getWeek_(this.$base.format(new Date(item), "yyyy-MM-dd"))
);
}
let dayx = [];
for (let i = 0; i < 7; i++) {
let item = new Date().getTime() - (6 - i) * 3600 * 24 * 1000;
dayx.push(this.$base.format(new Date(item), "MM.dd"));
}
timex = [...yearx, ...mouthx, ...weekx, ...dayx];
return timex;
},
十二、
//獲取後一天
let startTime = 2019-12-12
this.$base.format(new Date(new Date(startTime).getTime()+ 24 * 60 * 60 * 1000), "yyyy-MM-dd")+" 00:00:00"
// 2019-12-13 00:00:00
//獲取下一個月
let item = new Date().setMonth(new Date(startTime).getMonth() +1);
this.$base.format(new Date(item), "yyyy-MM")+"-01 00:00:00"
//2020-01-01 00:00:00
//獲取下一年
Number(this.$base.format(new Date(startTime), "yyyy")) +1;
十三、獲取當前月份的第一和最後一天
var now = new Date();
var month = now.getMonth() + 1;//js獲取到的是月份是 0-11 所以要加1
var year = now.getFullYear();
var nextMonthFirstDay = new Date([year,month + 1,1].join('-')).getTime();
var oneDay = 1000 * 24 * 60 * 60;
var monthLast = new Date(nextMonthFirstDay - oneDay).getDate()
console.log([year,month,1].join('-')) //2020-02-01
console.log([year,month,monthLast].join('-')) //2020-02-29
十四、數組內數據相加
sumData(data){
console.log("datadata",data)
let num
data.forEach(res=>{
if(!isNaN(Number(res.value))){
if(!num){
num = Number(res.value)
}else{
num+=Number(res.value)
}
}
})
if(!isNaN(Number(num))){
num =Number(num).toFixed(2)
}else{
num ="-"
}
return num
}