javascript - 遍历包含附加对象数组的对象数组。并进行一定的计算

Question

让我解释一下我在说什么。我有以下数组:

const days = [
{

    date: '2016-12-13T00:00:00.000Z',
    stats: [
      { name: 'A', sold: 34, },
      { name: 'B', sold: 3, },
      { name: 'C', sold: 26, },
    ],
  },
  {
    date: '2016-12-14T00:00:00.000Z',
    stats: [
      { name: 'D', sold: 34, },
      { name: 'E', sold: 3, },
      { name: 'F', sold: 26, },
    ],
  },
    {
    date: '2016-12-14T00:00:00.000Z',
    stats: [
      { name: 'D', sold: 34, },
      { name: 'E', sold: 3, },
      { name: 'F', sold: 26, },
    ],
  },
];

我想做的是找到每个 stat.name 的百分比，例如。如果我们合并所有售出的值(value)，我们得到:189 现在找到统计名称 B

的 %

(3 / 189) * 100

这会给我:1.58% 这表示该类别的已售商品的 %。

理想情况下我想要的结果应该是这样的:

const result = [
    { name: 'A', sold: 34, percentage: '17,98%' },
    { name: 'B', sold: 3, percentage: '1,58%', },
    { name: 'C', sold: 26, percentage: '13,75%', },
    { name: 'D', sold: 68, percentage: '35,97%', },
    { name: 'E', sold: 6, percentage: '3,17%' },
    { name: 'F', sold 52, percentage: '27,51%' },
];

到目前为止我做了什么:

const days = [
{
    date: '2016-12-13T00:00:00.000Z',
    stats: [
      { name: 'A', sold: 34, },
      { name: 'B', sold: 3, },
      { name: 'C', sold: 26, },
    ],
  },
  {
    date: '2016-12-14T00:00:00.000Z',
    stats: [
      { name: 'D', sold: 34, },
      { name: 'E', sold: 3, },
      { name: 'F', sold: 26, },
    ],
  },
    {
    date: '2016-12-14T00:00:00.000Z',
    stats: [
      { name: 'D', sold: 34, },
      { name: 'E', sold: 3, },
      { name: 'F', sold: 26, },
    ],
  },
];

let total = 0;
days.map(record => record.stats.map(category => total += category.sold)); // save the total;

const newStats = days.reduce(function (pastDay, currentDay) {
  const nextStats = currentDay.stats.map(function(stat) {
    const oldSold = pastDay.stats.find((old) => old.name === stat.name); // object that match by name.
    let newSold;
    if (oldSold) { // if matched
    	newSold = stat.sold + oldSold.sold // sum
    } else { // don't sum anything
    	newSold = stat.sold
    }
		stat.sold = newSold;
    stat.percentage = `${(newSold / total * 100).toFixed(2)}%`;
    return stat;
  });
  return {
    stats: nextStats,
  };
});

console.log(newStats);

哪些输出:

{
  "stats": [
    {
      "name": "D",
      "sold": 68,
      "percentage": "35.98%"
    },
    {
      "name": "E",
      "sold": 6,
      "percentage": "3.17%"
    },
    {
      "name": "F",
      "sold": 52,
      "percentage": "27.51%"
    }
  ]
}

A、B、C.都不见了..

整个事情有更好的方法吗？我真的不喜欢先绘制 map 并获得总数，然后再处理其余部分。有没有办法做得更好？谢谢...

Answer 1

您可以先收集售出数量，然后使用百分比呈现数组。

var days = [{ date: '2016-12-13T00:00:00.000Z', stats: [{ name: 'A', sold: 34, }, { name: 'B', sold: 3, }, { name: 'C', sold: 26, }, ], }, { date: '2016-12-14T00:00:00.000Z', stats: [{ name: 'D', sold: 34, }, { name: 'E', sold: 3, }, { name: 'F', sold: 26, }, ], }, { date: '2016-12-14T00:00:00.000Z', stats: [{ name: 'D', sold: 34, }, { name: 'E', sold: 3, }, { name: 'F', sold: 26, }, ], }, ],
    temp = Object.create(null),
    result = [],
    total = 0;

days.forEach(function (day) {
    day.stats.forEach(function (stat) {
        total += stat.sold;
        temp[stat.name] = (temp[stat.name] || 0) + stat.sold;
    });
}, Object.create(null));

result = Object.keys(temp).map(function (k) {
    return { name: k, sold: temp[k], percentage: (temp[k] * 100 / total).toFixed(2) + '%' };
});

console.log(result);

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