js的数组排序sort

1.默认–按照ASCII码进行升序排序

arr.sort()

2.自定义排序方式–a和b是相邻的两个数,a在前,b在后.如果返回正数，则a，b交换位置，负数和零则不变，所以也适用于json

arr.sort((a,b)=>{})
//1.升序 
if(a>b){
  return 1
}else{return -1}
//2.降序
if(a<b){
  return 1
}else{return -1}
//如果a,b是数字则可简写 
return a-b  //升序
return b-a  //降序

3.json
按照name升序

arr=[
{id:1,name:'a'},
{id:2,name:'b'},
{id:3,name:'c'},
{id:4,name:'d'}
]
arr.sort((a,b)=>{
  if(a.name>b.name){
      return 1
    }else{return -1}
})

按照name降序

arr=[
{id:1,name:'a'},
{id:2,name:'b'},
{id:3,name:'c'},
{id:4,name:'d'}
]
arr.sort((a,b)=>{
  if(a.name<b.name){
      return 1
    }else{return -1}
})