RosettaCodeData/Task/Palindrome-dates/JavaScript/palindrome-dates-1.js

45 lines
1.1 KiB
JavaScript

/**
* Adds zeros for 1 digit days/months
* @param date: string
*/
const addMissingZeros = date => (/^\d$/.test(date) ? `0${date}` : date);
/**
* Formats a Date to a string. If readable is false,
* string is only numbers (used for comparison), else
* is a human readable date.
* @param date: Date
* @param readable: boolean
*/
const formatter = (date, readable) => {
const year = date.getFullYear();
const month = addMissingZeros(date.getMonth() + 1);
const day = addMissingZeros(date.getDate());
return readable ? `${year}-${month}-${day}` : `${year}${month}${day}`;
};
/**
* Returns n (palindromesToShow) palindrome dates
* since start (or 2020-02-02)
* @param start: Date
* @param palindromesToShow: number
*/
function getPalindromeDates(start, palindromesToShow = 15) {
let date = start || new Date(2020, 3, 2);
for (
let i = 0;
i < palindromesToShow;
date = new Date(date.setDate(date.getDate() + 1))
) {
const formattedDate = formatter(date);
if (formattedDate === formattedDate.split("").reverse().join("")) {
i++;
console.log(formatter(date, true));
}
}
}
getPalindromeDates();