UTC => TZ conversion works
This commit is contained in:
parent
e4af522b88
commit
c30ecbd127
145
index.js
145
index.js
|
|
@ -1,27 +1,126 @@
|
||||||
/**
|
"use strict";
|
||||||
* take a date of assumed timezone and convert to utc
|
|
||||||
*
|
function fromUTCToTimeZone(date, timeZone) {
|
||||||
* @param {*} d
|
// ISO string or existing date object
|
||||||
* @param {*} tz
|
date = new Date(date);
|
||||||
* @returns
|
|
||||||
*/
|
|
||||||
function tzUTC(d, tz) {
|
|
||||||
// first calculate tz difference
|
|
||||||
var date = new Date();
|
|
||||||
var options = {
|
var options = {
|
||||||
year: 'numeric',
|
timeZone: timeZone,
|
||||||
month: 'numeric',
|
year: "numeric",
|
||||||
day: 'numeric',
|
month: "numeric",
|
||||||
hour: 'numeric',
|
day: "numeric",
|
||||||
minute: 'numeric',
|
|
||||||
second: 'numeric',
|
|
||||||
hour12: false,
|
hour12: false,
|
||||||
timeZone: tz
|
hour: "numeric",
|
||||||
|
minute: "numeric",
|
||||||
|
second: "numeric",
|
||||||
|
fractionalSecondDigits: 3,
|
||||||
};
|
};
|
||||||
var tzDate = new Intl.DateTimeFormat('en-US', options).format(date)
|
|
||||||
var diff = date - new Date(tzDate);
|
var tzOptions = Object.assign(
|
||||||
var minutes = Math.floor((diff / 1000) / 60);
|
{
|
||||||
var localTime = new Date(d);
|
timeZoneName: "long",
|
||||||
localTime.setMinutes(d.getMinutes() + minutes);
|
},
|
||||||
return localTime.toUTCString();
|
options
|
||||||
|
);
|
||||||
|
|
||||||
|
// Every country uses the same year and months, right?
|
||||||
|
var formater = new Intl.DateTimeFormat("default", tzOptions);
|
||||||
|
var parts = formater.formatToParts(date);
|
||||||
|
|
||||||
|
var whole = {};
|
||||||
|
parts.forEach(function (part) {
|
||||||
|
var val = part.value;
|
||||||
|
switch (part.type) {
|
||||||
|
case "literal":
|
||||||
|
// ignore separators and whitespace characters
|
||||||
|
return;
|
||||||
|
case "timeZoneName":
|
||||||
|
// keep as is - it's a string
|
||||||
|
break;
|
||||||
|
case "month":
|
||||||
|
// months are 0-indexed for new Date()
|
||||||
|
val = parseInt(val, 10) - 1;
|
||||||
|
break;
|
||||||
|
case "hour":
|
||||||
|
// because sometimes 24 is used instead of 0, make 24 0
|
||||||
|
val = parseInt(val, 10) % 24;
|
||||||
|
break;
|
||||||
|
case "fractionalSecond":
|
||||||
|
// fractionalSecond is a dumb name - should be millisecond
|
||||||
|
whole.millisecond = parseInt(val, 10);
|
||||||
|
return;
|
||||||
|
default:
|
||||||
|
val = parseInt(val, 10);
|
||||||
|
}
|
||||||
|
// whole.month = 0;
|
||||||
|
whole[part.type] = val;
|
||||||
|
});
|
||||||
|
|
||||||
|
whole.timeZone = timeZone;
|
||||||
|
whole.offset = getOffset(date, whole);
|
||||||
|
whole.toISOString = _toOffsetISOString;
|
||||||
|
return whole;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
function _toOffsetISOString() {
|
||||||
|
return toOffsetISOString(this);
|
||||||
|
}
|
||||||
|
|
||||||
|
function getOffset(utcDate, tzD2) {
|
||||||
|
var tzDate = new Date(toOffsetISOString(tzD2));
|
||||||
|
var diff = Math.round(tzDate.valueOf() - utcDate.valueOf()) / (60 * 1000);
|
||||||
|
return diff;
|
||||||
|
}
|
||||||
|
|
||||||
|
function p2(x) {
|
||||||
|
return String(x).padStart(2, "0");
|
||||||
|
}
|
||||||
|
|
||||||
|
function p3(x) {
|
||||||
|
return String(x).padStart(3, "0");
|
||||||
|
}
|
||||||
|
|
||||||
|
function formatOffset(minutes) {
|
||||||
|
if (!minutes) {
|
||||||
|
return "Z";
|
||||||
|
}
|
||||||
|
|
||||||
|
var h = Math.floor(Math.abs(minutes) / 60);
|
||||||
|
var m = Math.abs(minutes) % 60;
|
||||||
|
var offset = "";
|
||||||
|
if (minutes > 0) {
|
||||||
|
offset = "+";
|
||||||
|
} else if (minutes < 0) {
|
||||||
|
offset = "-";
|
||||||
|
}
|
||||||
|
|
||||||
|
// +0500, -0730
|
||||||
|
return (
|
||||||
|
offset + h.toString().padStart(2, "0") + m.toString().padStart(2, "0")
|
||||||
|
);
|
||||||
|
}
|
||||||
|
|
||||||
|
function toOffsetISOString(d) {
|
||||||
|
var offset = formatOffset(d.offset);
|
||||||
|
return (
|
||||||
|
`${d.year}-${p2(d.month + 1)}-${p2(d.day)}` +
|
||||||
|
`T${p2(d.hour)}:${p2(d.minute)}:${p2(d.second)}.${p3(
|
||||||
|
d.millisecond
|
||||||
|
)}${offset}`
|
||||||
|
);
|
||||||
|
}
|
||||||
|
|
||||||
|
function fromZonedToUTC(dt, tz) {}
|
||||||
|
|
||||||
|
module.exports = {
|
||||||
|
// bespoke date =>
|
||||||
|
// 2021-11-07T3:15:59-0500
|
||||||
|
toOffsetISOString: toOffsetISOString,
|
||||||
|
// -240 => -0400
|
||||||
|
formatOffset: formatOffset,
|
||||||
|
// [ "2021-11-07T08:15:59Z", "America/New_York" ]
|
||||||
|
// => "2021-11-07T03:15:59-0500" // 2021-11-07 03:15:59
|
||||||
|
fromUTCToTimeZone: fromUTCToTimeZone,
|
||||||
|
// [ "2021-11-07 03:15:59", "America/New_York" ]
|
||||||
|
// => "2021-11-07T03:15:59-0500" // 2021-11-07T08:15:59Z
|
||||||
|
fromZonedToUTC: fromZonedToUTC,
|
||||||
|
};
|
||||||
|
|
|
||||||
254
test.js
254
test.js
|
|
@ -1,133 +1,145 @@
|
||||||
var d = new Date("5/18/2019, 07:49:13");
|
"use strict";
|
||||||
// Fri May 17 2019 17:49:13 GMT-0400 (Eastern Daylight Time)
|
|
||||||
// utc should be Fri, 17 May 2019 21:49:13 GMT"
|
|
||||||
//
|
|
||||||
console.log("d:" + d)
|
|
||||||
console.log("tzUTC:" + tzUTC(d, 'Australia/Sydney'))
|
|
||||||
|
|
||||||
d = new Date("5/17/2019, 14:53:21");
|
var TZ = require("./");
|
||||||
console.log("d:" + d)
|
|
||||||
|
|
||||||
// Fri May 17 2019 17:53:21 GMT-0400 (Eastern Daylight Time)
|
// At this real UTC time, what does the timezone translate it to?
|
||||||
// utc "Fri, 17 May 2019 21:53:21 GMT"
|
[
|
||||||
|
//
|
||||||
|
// Start-of-DST Tests
|
||||||
|
//
|
||||||
|
|
||||||
console.log("tzUTC:" + tzUTC(d, 'America/Los_Angeles'))
|
// [Start]
|
||||||
|
// What time is '2021-03-14 01:15:59.000 in New York' in UTC? // 2021-03-14 06:15:59.000
|
||||||
|
// // 2021-03-14T01:15:59.000-0500
|
||||||
|
// What time is '2021-03-14 02:15:59.000 in New York' in UTC? // 2021-03-14 07:15:59.000
|
||||||
|
// // 2021-03-14T03:15:59.000-0400
|
||||||
|
// What time is '2021-03-14 03:15:59.000 in New York' in UTC? // 2021-03-14 07:15:59.000
|
||||||
|
// // 2021-03-14T03:15:59.000-0400
|
||||||
|
// What time is '2021-03-14 04:15:59.000 in New York' in UTC? // 2021-03-14 08:15:59.000
|
||||||
|
// // 2021-03-14T04:15:59.000-0400
|
||||||
|
// [End]
|
||||||
|
|
||||||
|
// 12:15am NY -0500 => -0400
|
||||||
|
{
|
||||||
|
inputs: ["2021-03-14T05:15:59.000Z", "America/New_York"],
|
||||||
|
result: "2021-03-14T00:15:59.000-0500",
|
||||||
|
},
|
||||||
|
{
|
||||||
|
inputs: ["2021-03-14T00:15:59.000-0500", "America/New_York"],
|
||||||
|
result: "2021-03-14T00:15:59.000-0500",
|
||||||
|
},
|
||||||
|
// 1:15am NY (non-DST)
|
||||||
|
{
|
||||||
|
inputs: ["2021-03-14T06:15:59.000Z", "America/New_York"],
|
||||||
|
result: "2021-03-14T01:15:59.000-0500",
|
||||||
|
},
|
||||||
|
{
|
||||||
|
inputs: ["2021-03-14T01:15:59.000-0500", "America/New_York"],
|
||||||
|
result: "2021-03-14T01:15:59.000-0500",
|
||||||
|
},
|
||||||
|
|
||||||
//////
|
// NOTE: Can't 2:15am NY, because it does not exist (skipped by DST)
|
||||||
////// 9:01 twice
|
|
||||||
//////
|
|
||||||
|
|
||||||
var d = new Date("3/10/2019, 01:59:00");
|
// 3:15am NY (DST)
|
||||||
console.log("tzUTC:" + tzUTC(d, 'America/Denver'));
|
{
|
||||||
// tzUTC:Sun, 10 Mar 2019 08:59:00 GMT
|
inputs: ["2021-03-14T07:15:59.000Z", "America/New_York"],
|
||||||
|
result: "2021-03-14T03:15:59.000-0400",
|
||||||
|
},
|
||||||
|
{
|
||||||
|
inputs: ["2021-03-14T03:15:59.000-0400", "America/New_York"],
|
||||||
|
result: "2021-03-14T03:15:59.000-0400",
|
||||||
|
},
|
||||||
|
// 4:15am NY
|
||||||
|
{
|
||||||
|
inputs: ["2021-03-14T08:15:59.000Z", "America/New_York"],
|
||||||
|
result: "2021-03-14T04:15:59.000-0400",
|
||||||
|
},
|
||||||
|
{
|
||||||
|
inputs: ["2021-03-14T04:15:59.000-0400", "America/New_York"],
|
||||||
|
result: "2021-03-14T04:15:59.000-0400",
|
||||||
|
},
|
||||||
|
|
||||||
var d = new Date("3/10/2019, 02:01:00");
|
//
|
||||||
console.log("tzUTC:" + tzUTC(d, 'America/Denver'));
|
// End-of-DST Tests
|
||||||
// tzUTC:Sun, 10 Mar 2019 09:01:00 GMT
|
//
|
||||||
|
|
||||||
var d = new Date("3/10/2019, 02:59:00");
|
// [Start]
|
||||||
console.log("tzUTC:" + tzUTC(d, 'America/Denver'));
|
// What time is '2021-11-07 01:15:59.000 in New York' in UTC? // 2021-11-07 05:15:59.000
|
||||||
// tzUTC:Sun, 10 Mar 2019 09:59:00 GMT
|
// // 2021-11-07T01:15:59.000-0400
|
||||||
|
// // 2021-11-07 06:15:59.000
|
||||||
|
// // 2021-11-07T01:15:59.000-0500
|
||||||
|
// What time is '2021-11-07 02:15:59.000 in New York' in UTC? // 2021-11-07 07:15:59.000
|
||||||
|
// // 2021-11-07T02:15:59.000-0500
|
||||||
|
// What time is '2021-11-07 03:15:59.000 in New York' in UTC? // 2021-11-07 08:15:59.000
|
||||||
|
// [End]
|
||||||
|
|
||||||
var d = new Date("3/10/2019, 03:01:00");
|
// 12:15am NY -0400 => -0500
|
||||||
console.log("tzUTC:" + tzUTC(d, 'America/Denver'));
|
{
|
||||||
// tzUTC:Sun, 10 Mar 2019 09:01:00 GMT
|
inputs: ["2021-11-07T04:15:59.000Z", "America/New_York"],
|
||||||
|
result: "2021-11-07T00:15:59.000-0400",
|
||||||
|
},
|
||||||
|
{
|
||||||
|
inputs: ["2021-11-07T00:15:59.000-0400", "America/New_York"],
|
||||||
|
result: "2021-11-07T00:15:59.000-0400",
|
||||||
|
},
|
||||||
|
// 1:15am NY (DST) -0400
|
||||||
|
// NOTE: 1:15am happens TWICE (with different offsets)
|
||||||
|
{
|
||||||
|
inputs: ["2021-11-07T05:15:59.000Z", "America/New_York"],
|
||||||
|
result: "2021-11-07T01:15:59.000-0400",
|
||||||
|
},
|
||||||
|
{
|
||||||
|
inputs: ["2021-11-07T01:15:59.000-0400", "America/New_York"],
|
||||||
|
result: "2021-11-07T01:15:59.000-0400",
|
||||||
|
},
|
||||||
|
// 1:15am NY (non-DST) -0500
|
||||||
|
{
|
||||||
|
inputs: ["2021-11-07T06:15:59.000Z", "America/New_York"],
|
||||||
|
result: "2021-11-07T01:15:59.000-0500",
|
||||||
|
},
|
||||||
|
{
|
||||||
|
inputs: ["2021-11-07T01:15:59.000-0500", "America/New_York"],
|
||||||
|
result: "2021-11-07T01:15:59.000-0500",
|
||||||
|
},
|
||||||
|
// 2:15am NY -0500
|
||||||
|
{
|
||||||
|
inputs: ["2021-11-07T07:15:59.000Z", "America/New_York"],
|
||||||
|
result: "2021-11-07T02:15:59.000-0500",
|
||||||
|
},
|
||||||
|
{
|
||||||
|
inputs: ["2021-11-07T02:15:59.000-0500", "America/New_York"],
|
||||||
|
result: "2021-11-07T02:15:59.000-0500",
|
||||||
|
},
|
||||||
|
// 3:15am NY
|
||||||
|
{
|
||||||
|
inputs: ["2021-11-07T08:15:59.000Z", "America/New_York"],
|
||||||
|
result: "2021-11-07T03:15:59.000-0500",
|
||||||
|
},
|
||||||
|
{
|
||||||
|
inputs: ["2021-11-07T03:15:59.000-0500", "America/New_York"],
|
||||||
|
result: "2021-11-07T03:15:59.000-0500",
|
||||||
|
},
|
||||||
|
|
||||||
//////
|
//
|
||||||
////// 8:01 never
|
// Positive Offset Test
|
||||||
//////
|
//
|
||||||
|
|
||||||
var d = new Date("11/03/2019, 01:59:00");
|
// 4:15am Colombo +0530 (not DST)
|
||||||
console.log("tzUTC:" + tzUTC(d, 'America/Denver'));
|
{
|
||||||
// tzUTC:Sun, 03 Nov 2019 07:59:00 GMT
|
inputs: ["2021-03-14T08:15:59.000Z", "Asia/Colombo"],
|
||||||
|
result: "2021-03-14T13:45:59.000+0530",
|
||||||
var d = new Date("11/03/2019, 02:01:00");
|
},
|
||||||
console.log("tzUTC:" + tzUTC(d, 'America/Denver'));
|
{
|
||||||
// tzUTC:Sun, 03 Nov 2019 09:01:00 GMT
|
inputs: ["2021-03-14T13:45:59.000+0530", "Asia/Colombo"],
|
||||||
|
result: "2021-03-14T13:45:59.000+0530",
|
||||||
var d = new Date("11/03/2019, 02:59:00");
|
},
|
||||||
console.log("tzUTC:" + tzUTC(d, 'America/Denver'));
|
].forEach(function (t) {
|
||||||
// tzUTC:Sun, 03 Nov 2019 09:59:00 GMT
|
var result = TZ.fromUTCToTimeZone.apply(TZ, t.inputs).toISOString();
|
||||||
|
if (t.result !== result) {
|
||||||
var d = new Date("11/03/2019, 03:01:00");
|
throw new Error(
|
||||||
console.log("tzUTC:" + tzUTC(d, 'America/Denver'));
|
"Invalid Conversion:\n" +
|
||||||
tzUTC:Sun, 03 Nov 2019 10:01:00 GMT
|
`\tExpected: ${t.result}\n` +
|
||||||
|
`\tActual: ${result}\n`
|
||||||
|
);
|
||||||
/*
|
|
||||||
Yes, that's a major use case. And one that can contact people according to their timezone. The daylight savings problem most likely won't affect us. But it could.
|
|
||||||
As a failsafe is there a way that you could detect daylight savings time and report it? Perhaps create 3 times and check that the difference on either side is exactly 1.5 hours?
|
|
||||||
*/
|
|
||||||
|
|
||||||
/*
|
|
||||||
But there's a second thing, more along the lines of a scheduler:
|
|
||||||
|
|
||||||
Given a target date in local time, produce the same local time a week later.
|
|
||||||
|
|
||||||
"I'm having lunch with John today at 12:30 pm. Schedule a lunch next week at 12:30pm."
|
|
||||||
|
|
||||||
The naive approach that almost always works is to simply add (7 x 24 x 60 x 60 x 1000), but that won't work if the lunch happened on either of these days:
|
|
||||||
|
|
||||||
var d = new Date("03/07/2019, 12:30:00"); // + (7 * 24 * 60 * 60 * 1000)
|
|
||||||
|
|
||||||
var d = new Date("11/01/2019, 12:30:00"); // + (7 * 24 * 60 * 60 * 1000)
|
|
||||||
|
|
||||||
In both instances my simple calendar would be off by an hour.
|
|
||||||
*/
|
|
||||||
|
|
||||||
/*
|
|
||||||
I think the solution will be:
|
|
||||||
|
|
||||||
srcMs = toMs(srcLocalDate)
|
|
||||||
targetMs = srcMs + diffMs
|
|
||||||
targetLocalDate = toLocal(targetMs)
|
|
||||||
targetMs += toMsAsIfUtc(srcLocalDate) - (toMsAsIfUtc(targetLocalDate) - diffMs)
|
|
||||||
return toLocalDate(targetMs)
|
|
||||||
*/
|
|
||||||
|
|
||||||
(function (exports) {
|
|
||||||
'use strict';
|
|
||||||
|
|
||||||
exports.TEST = function (myfn) {
|
|
||||||
|
|
||||||
var tests = [
|
|
||||||
{ name: "normal date"
|
|
||||||
, input: { d: '5/18/2019, 8:59:48 AM', tz: "America/Denver" }
|
|
||||||
, expected: 1558191588007
|
|
||||||
}
|
}
|
||||||
];
|
});
|
||||||
|
|
||||||
function next() {
|
|
||||||
var t = tests.shift();
|
|
||||||
var result;
|
|
||||||
if (!t) {
|
|
||||||
return true;
|
|
||||||
}
|
|
||||||
try {
|
|
||||||
result = Promise.resolve(myfn(t.input));
|
|
||||||
} catch(e) {
|
|
||||||
result = Promise.reject(e);
|
|
||||||
}
|
|
||||||
|
|
||||||
result.then(function (result) {
|
|
||||||
if (result === t.expected) {
|
|
||||||
return true;
|
|
||||||
}
|
|
||||||
throw new Error(t.name + ": result did not match expected: " + JSON.stringify(result) + " vs " + JSON.stringify(t.expected));
|
|
||||||
});
|
|
||||||
}
|
|
||||||
|
|
||||||
return next();
|
|
||||||
};
|
|
||||||
}('undefined' === typeof module ? window : module.exports));
|
|
||||||
|
|
||||||
runner.js:
|
|
||||||
(function (exports) {
|
|
||||||
'use strict';
|
|
||||||
|
|
||||||
var tzUtc = exports.tzUtc || require('./index.js').tzUtc;
|
|
||||||
var tester = exports.TEST || require('./test.js').TEST;
|
|
||||||
tester(tzUtc);
|
|
||||||
|
|
||||||
}('undefined' === typeof module ? window : module.exports));
|
|
||||||
|
|
|
||||||
Loading…
Reference in New Issue