Push element in an empty array

Question

I have an empty array:

const timeArray = []
const a = new Date(startTime_minTime)
const b = new Date(startTime_maxTime)
const disabledValueStart = new Date(maxStart)

// where startTime_minTime and startTime_maxTime are only two dates (date and time) and maxStart is the last value

Date.prototype.addHours = function (h) {
  this.setTime(this.getTime() + h * 60 * 30 * 1000)
  return this
}

//  Now I'm trying to do a while to populate the array 
while (a <= b) {
  timeArray.push(a)
  if (a !== disabledValueStart) {
    a.addHours(1)
  }
}

The problem is that my array has only the last value repeated for the number of elements that should populate it, how do I add one element at a time, so that I have them all at the end and not just the same repeated value?

So it not enter in the the if and add hour to variable 'a' ? — Jack23
– Jack23, Commented Mar 16, 2022 at 14:36
That depends on the values of a, b, and disabledValueStart. — evolutionxbox
– evolutionxbox, Commented Mar 16, 2022 at 14:37
I should populate the array with date except for disabledValueStart — Jack23
– Jack23, Commented Mar 16, 2022 at 14:51

twharmon · Accepted Answer · 2022-03-16 14:42:37Z

1

You are pushing the same date (a) to the array, over and over. Clone the date and push the clone. That way each item in the array is a different date.

Here is a working snippet. The key is timeArray.push(new Date(a)).

const timeArray = []
const a = new Date()
const b = new Date(a.getTime()+60*60*24*1000)
const disabledValueStart = new Date(a.getTime()-60*60*24*1000)

Date.prototype.addHours = function (h) {
  this.setTime(this.getTime() + h * 60 * 30 * 1000)
  return this
}

while (a <= b) {
  timeArray.push(new Date(a)) // here is the important change
  if (a !== disabledValueStart) {
    a.addHours(1)
  }
}

console.log(timeArray)

edited Mar 16, 2022 at 14:42

answered Mar 16, 2022 at 14:34

twharmon

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1 Comment

Andy Over a year ago

Please don't just dump a load of code. Explain what the problem was and document what your code does to solve it.

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