从两个时间范围数组（使用矩范围）计算联合时间范围

Question

我有两个moment-ranges 数组，代表两个人忙碌的时段。

计算包含他们忙碌的联合时间范围的数组的最佳方法是什么？如果个人的两个忙碌时段重叠，我需要代表他们忙碌的整个时段的时间范围。

这是一个例子：

const firstBusyPeriods = [ 
  { start: "2017-04-05T10:00:00Z", end: "2017-04-05T12:00:00Z" },
  { start: "2017-04-05T14:00:00Z", end: "2017-04-05T15:00:00Z" }
]

const secondBusyPeriods = [
  { start: "2017-04-05T08:00:00Z", end: "2017-04-05T11:00:00Z" },
  { start: "2017-04-05T16:00:00Z", end: "2017-04-05T17:00:00Z" }
]

生成的数组应如下所示：

const result = [
  { start: "2017-04-05T08:00:00Z", end: "2017-04-05T12:00:00Z" },
  { start: "2017-04-05T14:00:00Z", end: "2017-04-05T15:00:00Z" },
  { start: "2017-04-05T16:00:00Z", end: "2017-04-05T17:00:00Z" }
]

结果包含重叠繁忙时段的并集，然后包括个人之间不重叠的两个时段。

最好将两个数组连接起来，对结果数组进行排序，然后应用 reduce 函数吗？

或者最好是递归地遍历两个数组之一并生成一个堆栈，结果是并集和不相交的句点？

Answer 1

我想我会选择concat 和reduce：

const firstBusyPeriods = [{
    start: "2017-04-05T10:00:00Z",
    end: "2017-04-05T12:00:00Z"
  },
  {
    start: "2017-04-05T14:00:00Z",
    end: "2017-04-05T15:00:00Z"
  }
];

const secondBusyPeriods = [{
    start: "2017-04-05T08:00:00Z",
    end: "2017-04-05T11:00:00Z"
  },
  {
    start: "2017-04-05T16:00:00Z",
    end: "2017-04-05T17:00:00Z"
  }
];

const isBetween = function(range, date) {
  return range.start < date && range.end > date;
};

const rangesOverlap = function(rangeOne, rangeTwo) {
  return isBetween(rangeOne, rangeTwo.start) || isBetween(rangeOne, rangeTwo.end);
};

const mergeRanges = function(rangeOne, rangeTwo) {
  let newRange = {}

  if (isBetween(rangeOne, rangeTwo.start)) {
    newRange.start = rangeOne.start;
  } else {
    newRange.start = rangeTwo.start;
  }
  if (isBetween(rangeOne, rangeTwo.end)) {
    newRange.end = rangeOne.end;
  } else {
    newRange.end = rangeTwo.end;
  }

  return newRange;
};

const merge = function(rangeCollectionOne, rangeCollectionTwo) {
  let concatenatedCollections = rangeCollectionOne.concat(rangeCollectionTwo).sort((a,b) => a.start - b.start);
  let newCollection = concatenatedCollections.reduce((newCollection, range) => {
    let index = newCollection.findIndex(rangeToCheck => rangesOverlap(rangeToCheck, range));
    if (index !== -1) {
      newCollection[index] = mergeRanges(newCollection[index], range);
    } else {
      newCollection.push(range);
    }
    return newCollection;
  }, []);

  return newCollection;
}

console.log(merge(firstBusyPeriods, secondBusyPeriods));

首先我尝试了标准循环方法，我认为这里的递归甚至不需要完成任务。恕我直言，reduce 和 concat 方式更优雅。