javascript - Regarding the calculation of leave time

First of all, let’s talk about the rules for asking for leave:
1. If you ask for leave in the morning, the duration shall not be less than 3 hours
2. If you ask for leave in the afternoon, the duration shall not be less than 5 hours
3. Working hours: 9:00~18:00
4. There is one day at noon Hours of non-working time
Because of the company's system, overtime work is not paid but can be compensated, so the time must be accurate to the hour. Then the question comes:
1. If the time span of my request for leave is from morning to afternoon, it meets the rules, but the system calculation time will be one hour longer:

• My solution is: first determine whether the start and festival time are on the same day, then determine whether the start time is in the morning and whether the end time is in the afternoon. If both are satisfied, then subtract one hour from the time calculated by the system

2. If some people are stupid and choose the start and end time beyond working hours, for example, the end time is after 18:00, then they have to judge whether to deduct the time after 18:00

3. The most troublesome thing is if the holiday includes legal holidays, weekends and other special circumstances. There are also non-integer numbers that span days. For example, if you only ask for 11 a.m. three days later, how can you remove the period from 0:00 to 9:00 three days later?

1. If you ask for leave in the morning, the duration shall not be less than 3 hours
2. If you ask for leave in the afternoon, the duration shall not be less than 5 hours
3. Working hours: 9:00~18:00
4. There is one day at noon Hours of non-working time
Because of the company's system, overtime work is not paid but can be compensated, so the time must be accurate to the hour. Then the question comes:
1. If the time span of my leave is from morning to afternoon, it meets the rules, but the system calculation time will be one hour longer:

• My solution is: first determine whether the start and festival time are on the same day, then determine whether the start time is in the morning and whether the end time is in the afternoon. If both are satisfied, then subtract one hour from the time calculated by the system

Crossing days is actually the same as the same day. Anyway, the time for asking for leave every day is from 9:00 to 18:00

First judge
(Start-End)/(24X3600)=number of days. If it is greater than 1, it means it is spanning days. For example ：2016-08-30 10:30-2016-09-04 12:00. In fact, just calculate the situation of 08-30 and 09-04. The middle days are 7*3=21 hours

There are just a few situations, asking for leave in the morning, asking for leave in the afternoon, morning to afternoon
The if condition is a bit more troublesome

Start time >= 13 o'clock && End time <= 18 o'clock, take leave in the afternoon
The rest is basically span-segment. Just calculate the span-segment in morning and afternoon.

<code>你首先需要一个排班表用于判断是否是工作日。
如果小于9点，=9点，大于18点=18点，再用你1里面说的方法不久完了。</code>