Javascript .map() is not returning updated array

Question

Hi I'm having an array of date example [2019-02-21T04:06:32.000Z] and I want to convert the date into desired format [02/21/2019 4:06:32 AM]. So I'm using javascript map

dateArray.map( x => {
   return moment.tz(x, 'Etc/UTC').format('MM/DD/YYYY h:mm:ss A').toString()
});

after this I console date array but it is still showing [2019-02-21T04:06:32.000Z] but inside map() it is showing in desired format. What I'm doing wrong here? Can any one help me to solve this? Thank you.

map doesn't modify the array in-place, it will return a new array instead (use: dateArray = dateArray.map(...)) — Nick Parsons
– Nick Parsons, Commented Feb 21, 2019 at 8:50

Vladimir Bogomolov · Accepted Answer · 2019-02-21 08:51:10Z

7

.map is not mutating the existing array. You should do :

dataArray = dateArray.map( x => {
  return moment.tz(x, 'Etc/UTC').format('MM/DD/YYYY h:mm:ss A').toString()
});

answered Feb 21, 2019 at 8:51

Vladimir Bogomolov

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Comments

SoEzPz · Accepted Answer · 2020-01-14 22:48:55Z

0

If you must change the existing array then use a for loop.

dateArray = ['2019-02-21T04:06:32.000Z'];

for(let idx = 0; idx < dateArray.length; idx++){
  dateArray[idx] = moment.tz(dateArray[idx], 'Etc/UTC')
    .format('MM/DD/YYYY h:mm:ss A').toString();
}

answered Jan 14, 2020 at 22:48

SoEzPz

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