Reformat Date

Description

Given a date string in the form Day Month Year, where:

• Day is in the set {"1st", "2nd", "3rd", "4th", ..., "30th", "31st"}.
• Month is in the set {"Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"}.
• Year is in the range [1900, 2100].

Convert the date string to the format YYYY-MM-DD, where:

• YYYY denotes the 4 digit year.
• MM denotes the 2 digit month.
• DD denotes the 2 digit day.

 

Example 1:

Input: date = "20th Oct 2052"
Output: "2052-10-20"

Example 2:

Input: date = "6th Jun 1933"
Output: "1933-06-06"

Example 3:

Input: date = "26th May 1960"
Output: "1960-05-26"

 

Constraints:

• The given dates are guaranteed to be valid, so no error handling is necessary.

Solution(javascript)

/**
 * @param {string} date
 * @return {string}
 */
const reformatDate = function (date) {
  const arr = date.split(' ')
  const map = {
    Jan: 1,
    Feb: 2,
    Mar: 3,
    Apr: 4,
    May: 5,
    Jun: 6,
    Jul: 7,
    Aug: 8,
    Sep: 9,
    Oct: 10,
    Nov: 11,
    Dec: 12,
  }


  let day = ''
  const num = Number(arr[0].substr(0, 2))
  if (Number.isInteger(num)) {
    day = num
  } else {
    day = `0${arr[0][0]}`
  }
  if (day.length <= 1) {
    day = `0${day}`
  }
  let month = map[arr[1]].toString()
  if (month.length <= 1) {
    month = `0${month}`
  }
  const year = arr[2]
  return `${year}-${month}-${day}`
}