RosettaCodeData/Task/Last-Friday-of-each-month/Java/last-friday-of-each-month-4.java
2017-09-25 22:28:19 +02:00

55 lines
1.3 KiB
Java

(() => {
'use strict'
// lastWeekDaysOfYear :: Int -> Int -> [Date]
const lastWeekDaysOfYear = (iWeekDay, y) => [
31,
0 === y % 4 && 0 !== y % 100 || 0 === y % 400 ? 29 : 28,
31, 30, 31, 30, 31, 31, 30, 31, 30, 31
]
.map((d, m) =>
new Date(Date.UTC(
y, m, d - ((new Date(Date.UTC(y, m, d))
.getDay() + (7 - iWeekDay)) % 7))));
const days = {
sunday: 0,
monday: 1,
tuesday: 2,
wednesday: 3,
thursday: 4,
friday: 5,
saturday: 6
};
// GENERIC FUNCTIONS
// curry :: ((a, b) -> c) -> a -> b -> c
const curry = f => a => b => f(a, b);
// isoDateString :: Date -> String
const isoDateString = dte =>
dte.toISOString()
.substr(0, 10);
// range :: Int -> Int -> [Int]
const range = (m, n) =>
Array.from({
length: Math.floor(n - m) + 1
}, (_, i) => m + i);
// transpose :: [[a]] -> [[a]]
const transpose = lst =>
lst[0].map((_, iCol) =>
lst.map(row => row[iCol]));
// TEST
return transpose(
range(2015, 2019)
.map(curry(lastWeekDaysOfYear)(days.friday))
)
.map(row => row
.map(isoDateString)
.join('\t'))
.join('\n');
})();