我得到的是一組具有類別、日期和值的物件，就像這樣
const records =
[ { category: 'Cat 1', date: '2020-11-03', value: '300.00' }
, { category: 'Cat 2', date: '2020-11-03', value: '350.00' }
, { category: 'Cat 3', date: '2020-11-03', value: '50.00' }
, { category: 'Cat 1', date: '2020-11-13', value: '200.00' }
, { category: 'Cat 1', date: '2020-12-23', value: '100.00' }
, { category: 'Cat 2', date: '2020-11-23', value: '350.00' }
, { category: 'Cat 3', date: '2020-11-15', value: '50.00' }
, { category: 'Cat 3', date: '2021-01-15', value: '50.00' }
]
我想要得到的是每個類別、月份和每月總值的新陣列，如下所示：
const newRecords =
[ { category: 'Cat 1'
, totalPerMonth:
[ { month: '2020-11', totalMonthlyValue: '500.00' }
, { month: '2020-12', totalMonthlyValue: '100.00' }
] }
, { category: 'Cat 2'
, totalPerMonth:
[ { month: '2020-11', totalMonthlyValue: '700.00' }
] }
, { category: 'Cat 3'
, totalPerMonth:
[ { month: '2020-11', totalMonthlyValue: '100.00' }
, { month: '2021-01', totalMonthlyValue: '50.00' }
] } ]
uj5u.com熱心網友回復：
這邊走
const records =
[ { category: 'Cat 1', date: '2020-11-03', value: '300.00' }
, { category: 'Cat 2', date: '2020-11-03', value: '350.00' }
, { category: 'Cat 3', date: '2020-11-03', value: '50.00' }
, { category: 'Cat 1', date: '2020-11-13', value: '200.00' }
, { category: 'Cat 1', date: '2020-12-23', value: '100.00' }
, { category: 'Cat 2', date: '2020-11-23', value: '350.00' }
, { category: 'Cat 3', date: '2020-11-15', value: '50.00' }
, { category: 'Cat 3', date: '2021-01-15', value: '50.00' }
]
const result =
Object.values(
records.reduce((r,{category,date,value}) =>
{
let Ym = date.substring(0,7)
if (!r[category]) r[category] = { category, sum : {} }
if (!r[category].sum[Ym]) r[category].sum[Ym] = 0
r[category].sum[Ym] = Number(value)
return r
},{}
)).map(({category,sum}) =>
{
let totalPerMonth = Object.entries(sum).map(([month,sum])=>({month,totalMonthlyValue:sum.toFixed(2)}))
return { category,totalPerMonth }
},{})
console.log ( result ).as-console-wrapper {max-height: 100%!important;top:0 }uj5u.com熱心網友回復：
為此，您可以先按類別對資料進行分組，然后再按日期分組。然后，您需要將所有值相加并回傳定義的結構。這是一個正是這樣做的例子。
const records = [
{category: 'Cat 1', date: '2020-11-03', value: '300.00'},
{category: 'Cat 2', date: '2020-11-03', value: '350.00'},
{category: 'Cat 3', date: '2020-11-03', value: '50.00'},
{category: 'Cat 1', date: '2020-11-13', value: '200.00'},
{category: 'Cat 1', date: '2020-12-23', value: '100.00'},
{category: 'Cat 2', date: '2020-11-23', value: '350.00'},
{category: 'Cat 3', date: '2020-11-15', value: '50.00'},
{category: 'Cat 3', date: '2021-01-15', value: '50.00'}
];
// first you need to group it by category, you can do that by
// assigning a group indicator as key to an object and add an
// array as value containing all values. you can also use lodash's
// groupBy for grouping values.
const groupedRecords = {};
records.forEach(record => {
if (groupedRecords[record.category] === undefined) {
groupedRecords[record.category] = [];
}
groupedRecords[record.category].push(record);
});
// then, you need to go through each category group and group all
// records again by date. you can use the same pattern as above.
const result = Object.entries(groupedRecords).map(([category, recordsOfOneCategory]) => {
const groupedDates = {};
recordsOfOneCategory.forEach(record => {
// this regex extracts the date per month. it's probably better
// to use a date library for this part
const month = record.date.match(/^(\d{4}-\d{2})/)[1];
if (groupedDates[month] === undefined) {
groupedDates[month] = [];
}
groupedDates[month].push(record);
});
// now you have for each category group a group of dates with
// records in it. you now need to make a sum for each group of
// dates. you can do this by mapping the values into an array of
// only values and then sum them up using reduce.
const totalPerMonth = Object.entries(groupedDates).map(([month, items]) => ({
month,
totalMonthlyValue: items.map(item => parseFloat(item.value)).reduce((a,b) => a b).toFixed(2)
}));
return { category, totalPerMonth };
});
console.log(result);uj5u.com熱心網友回復：
您可以根據在array#reduce物件中使用的類別和月份進行分組。然后使用Object.values()and從此物件中提取所有值array#map。
const records = [ { category: 'Cat 1', date: '2020-11-03', value: '300.00' } , { category: 'Cat 2', date: '2020-11-03', value: '350.00' } , { category: 'Cat 3', date: '2020-11-03', value: '50.00' } , { category: 'Cat 1', date: '2020-11-13', value: '200.00' } , { category: 'Cat 1', date: '2020-12-23', value: '100.00' } , { category: 'Cat 2', date: '2020-11-23', value: '350.00' } , { category: 'Cat 3', date: '2020-11-15', value: '50.00' } , { category: 'Cat 3', date: '2021-01-15', value: '50.00' } ],
result = records.reduce((r, {category, date, value}) => {
const month = date.substring(0, 7);
r[category] ??= {category};
r[category][month] ??= {month, total: 0};
r[category][month].total = value;
return r;
},{}),
newRecords = Object
.values(result)
.map( ({category, ...rest}) =>
({ category,
totalPerMonth: Object.values(rest).map(({ month, total }) =>
({ month, totalMonthlyValue: total.toFixed(2) })
) }) );
console.log(newRecords);.as-console-wrapper { max-height: 100% !important; top: 0; }轉載請註明出處，本文鏈接：https://www.uj5u.com/ruanti/408336.html
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