let arry=[{a:1,b:2,c:3,d:4},{a:11,b:22,c:33,d:44},{a:111.b:222,c:333,d:444}]
let arry2=[]
arry.map(((item,index)=>{
arry2.push(Object.assign({},item,{mess1:item.c,mess2:item.d}))
}))
最后的结果
[{a:1,b:2,c:3,d:4,mess1:3,mess2:4},{a:11,b:22,c:33,d:44,mess1:33,mess2:44},{a:111.b:222,c:333,d:444,,mess1:333,mess2:444}]
