使用Utilities.formatDate，2017年12月31日为1秒= 1年

Question

Have curious results converting date using Utilities.formatDate()

function test_date_conversion_1() {
    var in_d_str = "12/31/2017"
    var new_d = Utilities.formatDate(new Date(in_d_str), "EET", "MM/dd/YYYY")
    return new_d
} 
// new_d = "12/31/2018"  2018?!

I've tried to develop a patch and get unexpected results for this function

function test_date_conversion(offset) {
    //offset = 1
    var in_d_str = "12/31/2017"
    var in_d = new Date(in_d_str)
    var in_d_epoch = in_d.getTime()
    var in_d_epoch_dep_1 = in_d_epoch+offset
    var in_d_d_dep_1 = new Date(in_d_epoch_dep_1)
    var new_d = Utilities.formatDate(in_d_d_dep_1, "EET", "MM/dd/YYYY")
}

if offset = 1 then new_d = "12/31/2018"

if offset = (-1) then new_d = "12/30/2017"

so 1 milisecond = 1 year?

EET = GMT+2 = script timezone

worksheet timezone = GMT+3

from debugger i've noticed that date is spoiled by Utilities.formatDate()

I've triede +/-1h, +/-1h+/-1sec offsets and still can't get just 12/31/2017 from 12/31/2017.

I've patched it like this

if (new_d == "12/31/2018")
    new_d = "12/31/2017";

but look for solid solution. thank you for answer in adwance.

Answer 1

The third parameter of formatDate(date, timeZone, format) is

a format per the SimpleDateFormat specification

For the SimpleDateFormat you use Y for the week year and y for the year. Since the week of 12/31/2017 is the first week of 2018, it will show as 2018.

Instead of using "MM/dd/YYYY" , use "MM/dd/yyyy" .