HD Challenge

test.js

class DateRange {
  constructor(start, end) {
    this.start = start
    this.end = end
  }
}

let date1= new Date(2021, 4, 1, 10, 10, 10)
let date2= new Date(2021, 4, 2, 10, 10, 10)
let date3= new Date(2021, 4, 3, 10, 10, 10)
let date4= new Date(2021, 4, 4, 10, 10, 10)
let date5= new Date(2021, 4, 5, 10, 10, 10)
let date6= new Date(2021, 4, 6, 10, 10, 10)

function merge_ranges(DateRangesArray) {

  if(DateRangesArray.lenght === 0) return false; //Or whatever error behavious we want...
  
  let results = [DateRangesArray[0]] // Set the reference Date_Range

  DateRangesArray.shift(); // Remove the reference Date_Range from the array to iterate

  DateRangesArray.forEach(range => {
    results.forEach((result, idx) => {

        let previousEnd = idx === 0 ? null : results[idx-1].end 
        let nextStart = idx < results.length - 1 ? results[idx + 1].start: null;

        // Extend the range if the new range overlaps, and ends after the begining of the result....
        if(range.start < result.start && range.end > result.start) {
          result.start = range.start
        } else if (range.start < result.start && range.end < result.start){
          //if we dont intersect on the lower end, there are two possibilities
          // 1 -- There is no results range before the range, in wich case, we add a range before...
          if(previousEnd === null) {
              results.unshift(new DateRange(range.start, range.end))
              previousEnd = range.end
          } else {
              // 2 -- There is another range before, in case we need to merge...
              // and replace the next item with the result of the merge
              results[idx - 1] = merge_ranges([range, results[idx - 1]])[0]
              previousEnd = results[idx - 1].end
          }
        }
        
        if (range.start > result.end) {
            //if we dont intersect at the end, there are two possibilities
            // 1 -- There is no range after the current range, in wich case, we add a range after...
            if(nextStart === null) {
                results.push(new DateRange(range.start, range.end))
                nextStart = range.start
            } else {
                // 2 -- There is another range ahead, in case we need to merge...
                // and replace the next item with the result of the merge
                results[idx + 1] = merge_ranges([range, results[idx + 1]])[0]
                nextStart = results[idx + 1].start
            }
        }
        
        // Otherwise, if the range overlaps but finishes after the current range and if it does not overlap with the next, extend
        if((range.start < result.end && range.end > result.end) && (nextStart === null || range.end < nextStart )) {
          result.end = range.end
        }
    })
  })
  
  return results;
}


function test_sample_1() {

  console.log('\n********* Testing the FIRST example : **********\n');
  let array = [new DateRange(date1, date3), new DateRange(date2, date4)]
  const result = merge_ranges(array)
  
  if (result[0] instanceof DateRange) {

    console.log('Got appropriate object instance')

    if(result[0].start !== date1)
       console.log(' X  Houston, we have a problem : First Date')
    else
        console.log('First date is ok')

    if(result[0].end !== date4)
       console.log(' X  Houston, we have a problem : Second date')
    else 
        console.log('Second date is Ok')
  }

  console.log(result)
  console.log('\n\n')
}

function test_sample_2() {

  console.log('\n********* Testing the SECOND example : **********\n')
  let array = [new DateRange(date1, date3), new DateRange(date2, date5), new DateRange(date4, date6)]
  const result = merge_ranges(array)
  
  if (result[0] instanceof DateRange) {

    console.log('Got appropriate object instance')

    if(result[0].start !== date1)
       console.log(' X  Houston, we have a problem : First Date')
    else
        console.log('First date is ok')

    if(result[0].end !== date6)
       console.log(' X  Houston, we have a problem : Second date')
    else 
        console.log('Second date is Ok')
  }

  console.log(result)
  console.log('\n\n')
}

function test_sample_3() {
    console.log('\n********* Testing the THIRD example : **********\n');
    let array = [new DateRange(date1, date2), new DateRange(date3, date5), new DateRange(date4, date6)]
    const result = merge_ranges(array)

    if (result.length !== 2) console.log('Not the right number of elements in response'); 
    
    if (result[0] instanceof DateRange) {
      console.log('Got appropriate object instance')
  
      if(result[0].start !== date1)
         console.log(' X  Houston, we have a problem : First Date')
      else
          console.log('First date is ok')
  
      if(result[0].end !== date2)
         console.log(' X  Houston, we have a problem : Second date')
      else 
          console.log('Second date is Ok')
    }

    if (result[1] instanceof DateRange) {
        console.log('Got appropriate object instance')
    
        if(result[1].start !== date3)
           console.log(' X  Houston, we have a problem : Second range - First Date')
        else
            console.log('First date is ok')
    
        if(result[1].end !== date6)
           console.log(' X  Houston, we have a problem : Second range - Second date')
        else 
            console.log('Second date is Ok')
      }
      
    console.log(result);
    console.log('\n\n')
  }

  function test_sample_4() {
    console.log('\n********* Testing the FOURTH example : **********\n');
    let array = [new DateRange(date1, date2), new DateRange(date3, date4), new DateRange(date5, date6)]
    const result = merge_ranges(array)

    if (result.length !== 3) console.log('Not the right number of elements in response'); 
    
    if (result[0] instanceof DateRange) {
      console.log('Got appropriate object instance')
  
      if(result[0].start !== date1)
         console.log(' X  Houston, we have a problem : First Date')
      else
          console.log('First date is ok')
  
      if(result[0].end !== date2)
         console.log(' X  Houston, we have a problem : Second date')
      else 
          console.log('Second date is Ok')
    }

    if (result[1] instanceof DateRange) {
        console.log('Got appropriate object instance')
    
        if(result[1].start !== date3)
           console.log(' X  Houston, we have a problem : Second range - First Date')
        else
            console.log('First date is ok')
    
        if(result[1].end !== date4)
           console.log(' X  Houston, we have a problem : Second range - Second date')
        else 
            console.log('Second date is Ok')
      }

      if (result[2] instanceof DateRange) {
        console.log('Got appropriate object instance')
    
        if(result[2].start !== date5)
           console.log(' X  Houston, we have a problem : Third range - First Date')
        else
            console.log('First date is ok')
    
        if(result[2].end !== date6)
           console.log(' X  Houston, we have a problem : Third range - Second date')
        else 
            console.log('Second date is Ok')
      }
      
    console.log(result)
    console.log('\n\n')
  }

  function test_sample_5() {
    console.log('\n********* Testing the FIFTH example : **********\n');
    let array = [new DateRange(date1, date3), new DateRange(date2, date6), new DateRange(date4, date5)]
    const result = merge_ranges(array)

    if (result.length !== 1) console.log('Not the right number of elements in response'); 
    
    if (result[0] instanceof DateRange) {
      console.log('Got appropriate object instance')
  
      if(result[0].start !== date1)
         console.log(' X  Houston, we have a problem : First Date')
      else
          console.log('First date is ok')
  
      if(result[0].end !== date6)
         console.log(' X  Houston, we have a problem : Second date')
      else 
          console.log('Second date is Ok')
    }
      
    console.log(result)
    console.log('\n\n')
  }

  function test_sample_6() {
    console.log('\n********* Testing the SIXTH example : **********\n');
    let array = [new DateRange(date1, date2), new DateRange(date3, date5), new DateRange(date4, date6)]
    const result = merge_ranges(array)

    if (result.length !== 2) console.log('Not the right number of elements in response'); 
    
    if (result[0] instanceof DateRange) {
      console.log('Got appropriate object instance')
  
      if(result[0].start !== date1)
         console.log(' X  Houston, we have a problem : First Date')
      else
          console.log('First date is ok')
  
      if(result[0].end !== date2)
         console.log(' X  Houston, we have a problem : Second date')
      else 
          console.log('Second date is Ok')
    }

    if (result[1] instanceof DateRange) {
      console.log('Got appropriate object instance')
  
      if(result[1].start !== date3)
         console.log(' X  Houston, we have a problem : First Date')
      else
          console.log('First date is ok')
  
      if(result[1].end !== date6)
         console.log(' X  Houston, we have a problem : Second date')
      else 
          console.log('Second date is Ok')
    }
      
    console.log(result)
    console.log('\n\n')
  }

test_sample_1()
test_sample_2()
test_sample_3()
test_sample_4()
test_sample_5()
test_sample_6()