合并日期最有效的方法是什么？

Question

Records in my database look like this:

From: 2012-01-16 06:20:00   To: 2012-01-16 06:30:00
From: 2012-01-16 06:30:00   To: 2012-01-16 06:40:00
From: 2012-01-16 06:40:00   To: 2012-01-16 06:50:00

And inside my application I have to combine them into 1 record looking like this:

From: 2012-01-16 06:20:00   To: 2012-01-16 06:50:00

Sometimes records are not in any order. They might look like that:

From: 2012-01-16 06:20:00   To: 2012-01-16 06:30:00
From: 2012-01-16 06:40:00   To: 2012-01-16 06:50:00
From: 2012-01-16 06:30:00   To: 2012-01-16 06:40:00

Answer 1

如果这是一个时间戳，则可以使用MIN（from）和MAX（to）。

Answer 2

Probably not the most efficient way, but I would do it like this:

let timeRanges = [];

timeRanges.push({
  from:  new Date(Date.parse('2012-01-16 06:20:00')),
  to: new Date(Date.parse('2012-01-16 06:30:00'))
});

timeRanges.push({
  from:  new Date(Date.parse('2012-01-16 06:40:00')),
  to: new Date(Date.parse('2012-01-16 06:50:00'))
});

timeRanges.push({
  from:  new Date(Date.parse('2012-01-16 06:30:00')),
  to: new Date(Date.parse('2012-01-16 06:40:00'))
});

let combinedTimeRange = {
  from: null,
  to: null
};

for(let timeRange of timeRanges) {
  if(combinedTimeRange.from === null 
    || combinedTimeRange.from.getTime() > timeRange.from.getTime()) {
      combinedTimeRange.from = timeRange.from;
  }

  if(combinedTimeRange.to === null 
    || combinedTimeRange.to.getTime() < timeRange.to.getTime()) {
      combinedTimeRange.to = timeRange.to;
  }
}

// just a test ..
console.log(combinedTimeRange.from.getMinutes());
console.log(combinedTimeRange.to.getMinutes());