如何从一系列日期范围中找到一个人的工作经验年限，工作日期可能重叠

Question

The goal is to use Javascript to UNIQUELY calculate the total years of a person's work experience, from an array of Date Ranges of the person's work history. There are Date Ranges which overlap (meaning, the person had multiple jobs within the overlapping period). Here is an example below and the date format is yyyy-mm-dd;

• 2001-02-01 to 2009-03-01
• 2004-06-01 to 2020-08-01
• 2005-04-01 to 2021-03-01
• 2008-07-01 to 2016-06-01

From the date ranges above, there are overlapping work dates. The correct computation of the person's years of work experience should be 20 years.

The problem I have is to creating an algorithm that can put into account, the overlapping periods within the person's four work histories and not count them as separate years of work experience Eg just summing up the years between each of the four job dates gives 48 years WHICH IS INCORRECT (The experience was over a 20-year period).

 var time_diff=0, yrs_diff=0; var jobExperience = [ {date_began:'2001-02-01', date_ended:'2009-03-01'}, {date_began:'2004-06-01', date_ended:'2020-08-01'}, {date_began:'2005-04-01', date_ended:'2021-03-01'}, {date_began:'2008-07-01', date_ended:'2016-06-01'} ]; for(let i=0; i<jobExperience.length; i++){ let date_1, date_2; let began = jobExperience[i].date_began.split('-'); let ended = jobExperience[i].date_ended.split('-'); date_1 = new Date(began[1]+'/'+began[2]+'/'+began[0]); date_2 = new Date(ended[1]+'/'+ended[2]+'/'+ended[0]); time_diff += date_2.getTime() - date_1.getTime(); } yrs_diff = parseInt(time_diff/(1000 * 3600 * 24 * 365)); console.log(yrs_diff);

The snippet above only just blindly adds up the years between each record of work history (This is not correct). Where I need some help is a clue or better still pseudocode or complete code on how to sum up the years between each record of work history but account for overlaps between work history dates and by so doing, overlapping periods are only counted once.

Answer 1

Here's the approach I've outlined in my comment:

For each period, turn the start and end date into a unique "month value", then add all month values of a period to a set.
The size of the set is the wanted number of months:

 const jobExperience = [ { date_began: '2001-02-01', date_ended: '2009-03-01' }, { date_began: '2004-06-01', date_ended: '2020-08-01' }, { date_began: '2005-04-01', date_ended: '2021-03-01' }, { date_began: '2008-07-01', date_ended: '2016-06-01' } ]; const months = new Set(); // convert date into unique integer month value based on year 1900 function m1900(yyyymmdd) { const [_, y, m, d] = yyyymmdd.match(/^(\d{4})-(\d{2})-(\d{2})$/).map(Number); return (y - 1900) * 12 + m; } jobExperience.forEach(job => { const m1 = m1900(job.date_began); const m2 = m1900(job.date_ended); for (let m = m1; m < m2; m++) months.add(m); }); console.log("years:", months.size / 12);

Answer 2

Here is a "Brute Force" approach.

• Extract all the unique years
• Sort them
• Find the difference between the latest to the oldest year

(Assuming that all the years in the dataset belong to a single field; Different fields should not be part of the same dataset)

Eg: [2001, 2004, 2005, 2008, 2009, 2016, 2020, 2021] => Working for 20 years.

A caveat with this method is that it fails to account for the months .

A solution to the same would be [NOT SURE] to convert the months to a year (month/12) and adding the same to the preceding year (Like Feb 2001 => 2001.166).

Another caveat is that it fails to account for any break taken in between. (As Pointed out in the Comments).