在Javascript中数组对象(json)里元素相同的操作

1、数组对象元素相同,分组显示

let arry = [
    { expensedate: '2018/09/29', amount: 1, type: '交通费' },
    { expensedate: '2018/08/19', amount: 2.5, type: '补贴费' },
    { expensedate: '2018/09/29', amount: 6.3, type: '住宿费' },
    { expensedate: '2018/01/19', amount: 18.5, type: '采购经费' },
    { expensedate: '2018/09/22', amount: 8.4, type: '活动经费' },
    { expensedate: '2018/09/29', amount: 7.9, type: '材料打印费' }
]
let items = [];
let datelist = {};
for (let i = 0; i < arry.length; i++) {
    let element = arry[i];
    if (!datelist[element.expensedate]) {
        items.push({
            expensedate: element.expensedate,
            subitems: [element]
        })
        datelist[element.expensedate] = element;
    } else {
        for (let j = 0; j < items.length; j++) {
            let subment = items[j];
            if (subment.expensedate == element.expensedate) {
                subment.subitems.push(element)
            }
        }
    }

}
console.log(items);

2、数组对象元素相同,汇总显示

let arrys = [
    { expensedate: '2018/09/29', amount: 1, type: '交通费' },
    { expensedate: '2018/08/19', amount: 2.5, type: '补贴费' },
    { expensedate: '2018/09/29', amount: 6.3, type: '交通费' },
    { expensedate: '2018/01/08', amount: 18.5, type: '采购经费' },
    { expensedate: '2018/09/22', amount: 8.4, type: '活动经费' },
    { expensedate: '2018/09/29', amount: 7.9, type: '交通费' }
]
let otheritems = [];
let list = {};
for (let i = 0; i < arrys.length; i++) {
    let element = arry[i].expensedate;
    if (list[element]) {
        list[element].expensedate = list[element].expensedate;
        list[element].amount = list[element].amount + arrys[i].amount;
    } else {
        list[element] = {};
        list[element].expensedate = arrys[i].expensedate;
        list[element].amount = arrys[i].amount;
    }
    list[element].type = arrys[i].type;
}
//对象转数组
for (var i in list) {
    otheritems.push(list[i])
}
console.log(otheritems)