后台返回对象数组，对象属性相同时，只取一个对象

后台返回的数据：

[
  {confirmCharge: "0.00", orderId: "--", changeId: "1", realName: "王五", totalConfirmCharge: "0.00",…},
  {confirmCharge: "0.00", orderId: "288783482594267136", changeId: "", realName: "王五",…},
  {confirmCharge: "0.00", orderId: "--", changeId: "1", realName: "王五", totalConfirmCharge: "0.00",…},
  {1: 1, totalOrderTimes: 2}
]

要求：

changeId相同的项，只取一条数据，changeId为空，原样取出，最后一条数据不取

目标数据：

[
  {confirmCharge: "0.00", orderId: "--", changeId: "1", realName: "王五", totalConfirmCharge: "0.00",…},
  {confirmCharge: "0.00", orderId: "288783482594267136", changeId: "", realName: "王五",…}
]

思路：

把changeId属性值存到一个arr数组，存目标数据前将每一项的changeId和arr中的值进行对比，如果相同，就不取该项

实现代码：

var arr = [],ifContain 
var objArr = [
  {confirmCharge: "0.00", orderId: "--", changeId: "1", realName: "王五", totalConfirmCharge: "0.00",…},
  {confirmCharge: "0.00", orderId: "288783482594267136", changeId: "", realName: "王五",…},
  {confirmCharge: "0.00", orderId: "--", changeId: "1", realName: "王五", totalConfirmCharge: "0.00",…},
  {1: 1, totalOrderTimes: 2}
]
var newArr = []
// console.log(arr) 
// arr用来存储changeId  ifContain用来判断当前元素中的changId是否在arr中
newArr.push(objArr[0])
if(objArr[0].changeId){
    arr.push(objArr[0].changeId)
}

for(var i=1;i<objArr.length-1;i++){
    if(!objArr[i].changeId){
        newArr.push(objArr[i])
    }if(objArr[i].changeId){
        ifContain = contains(arr,objArr[i].changeId)
        if(!ifContain){
            newArr.push(objArr[i])
            arr.push(objArr[i].changeId)
        }
    }
}

    // JS判断元素是否在数组内的实现代码
contains(arr,obj) {
    let length = arr.length
    while(length--){
        if(arr[length] === obj){
            return true
        }
    }
    return false
}