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108
README.md
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@ -9,58 +9,36 @@ XTZ is a poor man's `Temporal` polyfill, but just for time zones. \
Demo: <https://therootcompany.github.io/tz.js/>
```js
// What's the current time, in ISO format?
// What's the current time, in ISO+Offset format?
TZ.toLocalISOString(new Date()); // "2021-11-07T03:15:59.000-0500"
TZ.timeZone(); // "America/New_York"
```
> What UTC time will it be when it's 3:15am in New York?
```js
// Relative New York time to Absolute UTC Time
TZ.toUTCISOString("2021-11-07 03:15:59.000", "America/New_York");
// What will the ISO+Offset datetime string be
// when it's 3:15am in New York?
//
// (Relative New York time to Absolute ISO+Offset Time)
TZ.toOffsetISOString("2021-11-07 03:15:59.000", "America/New_York");
// "2021-11-07T03:15:59.000-0500"
```
```js
var tzDate = TZ.toUTC("2021-11-07 03:15:59.000", "America/New_York");
// {
// year: 2021, month: 10, day: 7,
// hour: 3, minute: 15, second: 59, millisecond: 0,
// offset: -300, timeZoneName: "Eastern Standard Time"
// }
// What time will it be in New York
// when it's 7:15am UTC?
//
// (Absolute UTC Zulu time to Relative New York time)
tzDate.toISOString();
// "2021-11-07T03:15:59.000-0500"
// (same as "2021-11-07T08:15:59.000Z")
```
> What time will it be in New York when it's 7:15am UTC?
```js
// Absolute UTC time to Relative New York time
TZ.toTimeZoneISOString("2021-03-14T07:15:59.000Z", "America/New_York");
// "2021-03-14T03:15:59.000-0400"
```
```js
var utcDate = TZ.toTimeZone("2021-03-14T07:15:59.000Z", "America/New_York");
// {
// year: 2021, month: 2, day: 14,
// hour: 3, minute: 15, second: 59, millisecond: 0,
// offset: -240, timeZoneName: "Eastern Daylight Time"
// }
utcDate.toISOString();
// "2021-03-14T03:15:59.000-0400"
// (same as "2021-11-07T07:15:59.000Z")
```
# Features
- [x] Translate a UTC time to a Time Zone
- [x] Translate a Zoned time to UTC
- [x] Translate a UTC Zulu time to a Time Zone
- [x] Translate a Zoned time to ISO+Offset
- [x] Handles **Daylight Savings**, Weird Time Zones, etc...
- [x] Well-tested `npm run test`
- [x] Lightweight (No deps)
@ -108,33 +86,46 @@ https://www.youtube.com/playlist?list=PLxki0D-ilnqa6horOJ2G18WMZlJeQFlAt
- `toLocalISOString(dateOrNull)`
- `toTimeZone(utcDate, timeZone)`
- `toTimeZoneISOString(isoString, timeZone)`
- `toUTC(dtString, timeZone)`
- `toUTCISOString(dtString, timeZone)`
- `fromTimeZone(dtString, timeZone)`
- `toOffsetISOString(dtString, timeZone)`
## `toTimeZone(utcDate, timeZone)`
> Convert UTC into a Target Time Zone
Use ISO timestamps representing the absolute UTC time (with or without offset):
Use ISO timestamps representing the absolute UTC time (ISO with or without offset):
```txt
"2021-11-07T08:15:59.000Z"
```
Convert directly to an ISO String:
```js
var utcDate = TZ.toTimeZone("2021-03-14T07:15:59.000Z", "America/New_York");
// {
// year: 2021, month: 2, day: 14,
// hour: 3, minute: 15, second: 59, millisecond: 0,
// offset: -240, timeZoneName: "Eastern Daylight Time"
// }
utcDate.toISOString();
// "2021-03-14T03:15:59.000-0400"
// (same as "2021-11-07T07:15:59.000Z")
```
### Convert directly to an ISO String:
```js
TZ.toTimeZoneISOString("2021-11-07T08:15:59.000Z", "America/New_York");
// "2021-11-07T03:15:59.000-0500"
```
Or use our bespoke (custom) date object:
### Or use our bespoke (custom) date object:
```js
var tzDate = TZ.toTimeZone("2021-11-07T08:15:59.000Z", "America/New_York");
```
You can also use a date object with an absolute UTC time:
### You can also use a date object with an absolute ISO time:
```js
var tzDate = TZ.toTimeZone(
@ -148,16 +139,16 @@ console.log(tzDate.toISOString());
// "2021-11-07T03:15:59.000-0500"
```
Our ISO Strings + Offsets work with JavaScript's native Date object!!
### Our ISO Strings + Offsets work with JavaScript's native Date object!!
```js
new Date("2021-11-07T03:15:59.000-0500").toISOString());
// "2021-11-07T08:15:59.000Z"
```
## `toUTC(dtString, timeZone)`
## `fromTimeZone(dtString, timeZone)`
> Convert a Target Time Zone into UTC
> Convert a Target Time Zone into ISO
Use ISO-like timestamps representing the _local_ time in the target time zone:
@ -165,24 +156,39 @@ Use ISO-like timestamps representing the _local_ time in the target time zone:
"2021-11-0 03:15:59.000"
```
Convert directly to an offset ISO String:
```js
var tzDate = TZ.fromTimeZone("2021-11-07 03:15:59.000", "America/New_York");
// {
// year: 2021, month: 10, day: 7,
// hour: 3, minute: 15, second: 59, millisecond: 0,
// offset: -300, timeZoneName: "Eastern Standard Time"
// }
tzDate.toISOString();
// "2021-11-07T03:15:59.000-0500"
// (same as "2021-11-07T08:15:59.000Z")
```
### Convert directly to an offset ISO String:
```js
TZ.toUTCISOString("2021-11-07 03:15:59.000", "America/New_York");
TZ.toOffsetISOString("2021-11-07 03:15:59.000", "America/New_York");
// "2021-11-07T03:15:59.000-0500"
```
Or our bespoke date object:
### Or our bespoke date object:
```js
var utcDate = TZ.toUTC("2021-11-07 03:15:59.000", "America/New_York");
var utcDate = TZ.fromTimeZone("2021-11-07 03:15:59.000", "America/New_York");
```
### Use a Date as a source time
You can also use a date object as the source time, but the date's UTC time will be treated as **_relative to time
zone_** rather than absolute (this is a workaround for JavaScript's lack of bi-directional timezone support).
```js
var utcDate = TZ.toUTC(
var utcDate = TZ.fromTimeZone(
new Date("2021-11-07T03:15:59.000Z"),
"America/New_York"
);
@ -207,7 +213,7 @@ Q: What happens in March when 2am is skipped?
- A: Although 2am is not a valid time, rather than throwing an error this library will resolve to 1am instead, which
is an hour early in real ("tick-tock" or "monotonic") time.
```js
var utcDate = TZ.toUTC("2021-03-14 02:15:59.000", "America/New_York");
var utcDate = TZ.fromTimeZone("2021-03-14 02:15:59.000", "America/New_York");
utcDate.toISOString();
// "2021-03-14T02:15:59.000-0400"
// (same as "2021-03-14T01:15:59.000-0500")
@ -218,7 +224,7 @@ Q: What happens in November when 1am happens twice?
- A: Although both 1ams are distinguishable with ISO offset times, only the first can be resolved from a local time
with this library.
```js
var utcDate = TZ.toUTC("2021-11-07 01:15:59.000", "America/New_York");
var utcDate = TZ.fromTimeZone("2021-11-07 01:15:59.000", "America/New_York");
utcDate.toISOString();
// "2021-11-07T01:15:59.000-0400", same as "2021-11-07T05:15:59.000Z"
// (an hour before the 2nd 1am at "2021-11-07T01:15:59.000-0500")

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@ -22,9 +22,9 @@ var XTZ;
console.info();
console.info("\t// during daylight savings");
console.info(`\tXTZ.toUTC("2021-03-14 08:15:59.000", "America/New_York")`);
console.info(`\tXTZ.fromTimeZone("2021-03-14 08:15:59.000", "America/New_York")`);
console.info(`\ttzDate.toISOString()`);
tzDate = XTZ.toUTC("2021-03-14 08:15:59.000", "America/New_York");
tzDate = XTZ.fromTimeZone("2021-03-14 08:15:59.000", "America/New_York");
console.info(
"\t" + tzDate.toISOString(),
"// same as",
@ -33,9 +33,9 @@ var XTZ;
console.info();
console.info("\t// during standard time");
console.info(`\tXTZ.toUTC("2021-11-07 08:15:59.000", "America/New_York")`);
console.info(`\tXTZ.fromTimeZone("2021-11-07 08:15:59.000", "America/New_York")`);
console.info(`\ttzDate.toISOString()`);
tzDate = XTZ.toUTC("2021-11-07 08:15:59.000", "America/New_York");
tzDate = XTZ.fromTimeZone("2021-11-07 08:15:59.000", "America/New_York");
console.info(
"\t" + tzDate.toISOString(),
"// same as",
@ -65,9 +65,9 @@ var XTZ;
console.info();
console.info("\t// during standard time");
console.info(`\tXTZ.toUTC("2021-11-07T08:15:59.000Z", "America/New_York")`);
console.info(`\tXTZ.fromTimeZone("2021-11-07T08:15:59.000Z", "America/New_York")`);
console.info(`\ttzDate.toISOString()`);
tzDate = XTZ.toUTC("2021-11-07T08:15:59.000Z", "America/New_York");
tzDate = XTZ.fromTimeZone("2021-11-07T08:15:59.000Z", "America/New_York");
console.info(
"\t" + tzDate.toISOString(),
"// same as",

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@ -99,8 +99,8 @@ String(((new Date()).getTimezoneOffset() % 60)).padStart(2, '0')</code></pre>
<hr />
<form class="js-tz2utc">
<h3>Relative TimeZone to Absolute UTC:</h3>
<pre><code>XTZ.toUTC("<span class="js-dtx-tz">YYYY-03-14 03:15:69.000</span>", "<span class="js-tzx-tz">UTC</span>")
<h3>TimeZone-Relative (Local) to Absolute (ISO+Offset) String:</h3>
<pre><code>XTZ.fromTimeZone("<span class="js-dtx-tz">YYYY-03-14 03:15:69.000</span>", "<span class="js-tzx-tz">UTC</span>")
.toISOString()
// <span class="js-myx-dt-tz"></span></code></pre>
<label>
@ -130,14 +130,14 @@ String(((new Date()).getTimezoneOffset() % 60)).padStart(2, '0')</code></pre>
</label>
<br />
<br />
<button type="submit">Convert to UTC!</button>
<button type="submit">Convert to ISO+Offset!</button>
<br />
</form>
<hr />
<form class="js-utc2tz">
<h3>Absolute UTC to Relative TimeZone</h3>
<h3>Absolute (UTC) to TimeZone-Relative (ISO+Offset) String:</h3>
<pre><code>XTZ.toTimeZone("<span class="js-dtx-utc">YYYY-03-14 03:15:69.000</span>", "<span class="js-tzx-utc">UTC</span>")
.toISOString()
// <span class="js-myx-dt-utc"></span></code></pre>
@ -201,17 +201,17 @@ Asia/Kolkata +0530 (No DST) (30-min)</pre
}
function translate(dt, tz, tz2) {
var utc = new Date(XTZ.toUTC(dt, tz).toISOString());
var utc = new Date(XTZ.fromTimeZone(dt, tz).toISOString());
if (!tz2) {
return utc;
}
return XTZ.toTimeZone(utc, tz2);
}
function toUTC() {
function fromTimeZone() {
var curDt = $(".js-dt-tz").value;
var curTz = $(".js-tz-tz").value;
$(".js-my-dt-tz").value = XTZ.toUTC(curDt, curTz).toISOString();
$(".js-my-dt-tz").value = XTZ.fromTimeZone(curDt, curTz).toISOString();
$(".js-dtx-tz").innerText = curDt;
$(".js-tzx-tz").innerText = curTz;
@ -265,10 +265,10 @@ Asia/Kolkata +0530 (No DST) (30-min)</pre
$("form.js-tz2utc").addEventListener("submit", function (ev) {
ev.preventDefault();
ev.stopPropagation();
toUTC();
fromTimeZone();
});
toUTC();
fromTimeZone();
toTZ();
xTZ();
</script>

View File

@ -1,8 +1,12 @@
{
"name": "xtz",
"version": "1.1.1",
"version": "1.3.1",
"description": "A fast, lightweight, zero-dependency library to translate between Time Zones and UTC with native Intl.DateTimeFormat in ~100 LoC. For Node.js & Browsers.",
"main": "xtz.js",
"files": [
"xtz.js",
"tolocalisostring.js"
],
"scripts": {
"test": "node ./test.js",
"build": "uglifyjs ./xtz.js > ./xtz.min.js ; gzip -k -f ./xtz.min.js"

53
test.js
View File

@ -6,7 +6,7 @@ function testUtcToTz(t) {
var result = TZ.toTimeZone.apply(TZ, t.inputs).toISOString();
if (t.result !== result) {
throw new Error(
`Invalid UTC to TZ conversion for ${t.desc}:\n` +
`Invalid UTC/ISO+Offset to TZ conversion for ${t.desc}:\n` +
`\tExpected: ${t.result}\n` +
`\tActual: ${result}\n`
);
@ -15,7 +15,8 @@ function testUtcToTz(t) {
function testTzToUtc(t) {
var result = TZ.toUTC.apply(TZ, t.inputs);
if (t.result !== result.toISOString()) {
var result2 = TZ.fromTimeZone.apply(TZ, t.inputs);
if (t.result !== result.toISOString() || t.result !== result2.toISOString()) {
console.log(result);
throw new Error(
`Invalid TZ to UTC conversion for ${t.desc}:\n` +
@ -44,23 +45,23 @@ function testTzToUtc(t) {
// 12:15am NY -0500 => -0400
{
desc: "UTC to 12:15am NY EST",
desc: "UTC Zulu to 12:15am NY EST",
inputs: ["2021-03-14T05:15:59.000Z", "America/New_York"],
result: "2021-03-14T00:15:59.000-0500",
},
{
desc: "UTC to 12:15am NY EST (2)",
desc: "ISO+Offset to 12:15am NY EST (2)",
inputs: ["2021-03-14T00:15:59.000-0500", "America/New_York"],
result: "2021-03-14T00:15:59.000-0500",
},
// 1:15am NY (non-DST)
{
desc: "UTC to 1:15am NY EST",
desc: "UTC Zulu to 1:15am NY EST",
inputs: ["2021-03-14T06:15:59.000Z", "America/New_York"],
result: "2021-03-14T01:15:59.000-0500",
},
{
desc: "UTC to 1:15am NY EST (2)",
desc: "ISO+Offset to 1:15am NY EST (2)",
inputs: ["2021-03-14T01:15:59.000-0500", "America/New_York"],
result: "2021-03-14T01:15:59.000-0500",
},
@ -69,23 +70,23 @@ function testTzToUtc(t) {
// 3:15am NY (DST)
{
desc: "UTC to 3:15am NY EDT",
desc: "UTC Zulu to 3:15am NY EDT",
inputs: ["2021-03-14T07:15:59.000Z", "America/New_York"],
result: "2021-03-14T03:15:59.000-0400",
},
{
desc: "UTC to 3:15am NY EDT (2)",
desc: "ISO+Offset to 3:15am NY EDT (2)",
inputs: ["2021-03-14T03:15:59.000-0400", "America/New_York"],
result: "2021-03-14T03:15:59.000-0400",
},
// 4:15am NY
{
desc: "UTC to 4:15am NY EDT",
desc: "UTC Zulu to 4:15am NY EDT",
inputs: ["2021-03-14T08:15:59.000Z", "America/New_York"],
result: "2021-03-14T04:15:59.000-0400",
},
{
desc: "UTC to 4:15am NY EDT (2)",
desc: "ISO+Offset to 4:15am NY EDT (2)",
inputs: ["2021-03-14T04:15:59.000-0400", "America/New_York"],
result: "2021-03-14T04:15:59.000-0400",
},
@ -106,57 +107,57 @@ function testTzToUtc(t) {
// 12:15am NY -0400 => -0500
{
desc: "UTC to 2021 Nov 7, 12:15am NY EDT",
desc: "UTC Zulu to 2021 Nov 7, 12:15am NY EDT",
inputs: ["2021-11-07T04:15:59.000Z", "America/New_York"],
result: "2021-11-07T00:15:59.000-0400",
},
{
desc: "UTC to 2021 Nov 7, 12:15am NY EDT (2)",
desc: "ISO+Offset to 2021 Nov 7, 12:15am NY EDT (2)",
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)
{
desc: "UTC to 2021 Nov 7, 1:15am NY EDT",
desc: "UTC Zulu to 2021 Nov 7, 1:15am NY EDT",
inputs: ["2021-11-07T05:15:59.000Z", "America/New_York"],
result: "2021-11-07T01:15:59.000-0400",
},
{
desc: "UTC to 2021 Nov 7, 1:15am NY EDT (2)",
desc: "ISO+Offset to 2021 Nov 7, 1:15am NY EDT (2)",
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
{
desc: "UTC to 2021 Nov 7, 1:15am NY EST",
desc: "UTC Zulu to 2021 Nov 7, 1:15am NY EST",
inputs: ["2021-11-07T06:15:59.000Z", "America/New_York"],
result: "2021-11-07T01:15:59.000-0500",
},
{
desc: "UTC to 2021 Nov 7, 1:15am NY EST (2)",
desc: "ISO+Offset to 2021 Nov 7, 1:15am NY EST (2)",
inputs: ["2021-11-07T01:15:59.000-0500", "America/New_York"],
result: "2021-11-07T01:15:59.000-0500",
},
// 2:15am NY -0500
{
desc: "UTC to 2021 Nov 7, 2:15am NY EST",
desc: "UTC Zulu to 2021 Nov 7, 2:15am NY EST",
inputs: ["2021-11-07T07:15:59.000Z", "America/New_York"],
result: "2021-11-07T02:15:59.000-0500",
},
{
desc: "UTC to 2021 Nov 7, 2:15am NY EST (2)",
desc: "ISO+Offset to 2021 Nov 7, 2:15am NY EST (2)",
inputs: ["2021-11-07T02:15:59.000-0500", "America/New_York"],
result: "2021-11-07T02:15:59.000-0500",
},
// 3:15am NY
{
desc: "UTC to 2021 Nov 7, 3:15am NY EST",
desc: "UTC Zulu to 2021 Nov 7, 3:15am NY EST",
inputs: ["2021-11-07T08:15:59.000Z", "America/New_York"],
result: "2021-11-07T03:15:59.000-0500",
},
{
desc: "UTC to 2021 Nov 7, 3:15am NY EST (2)",
desc: "ISO+Offset to 2021 Nov 7, 3:15am NY EST (2)",
inputs: ["2021-11-07T03:15:59.000-0500", "America/New_York"],
result: "2021-11-07T03:15:59.000-0500",
},
@ -167,27 +168,29 @@ function testTzToUtc(t) {
// Colombo +0530 (not DST)
{
desc: "UTC to Asia/Colombo (1)",
desc: "UTC Zulu to Asia/Colombo (1)",
inputs: ["2021-03-14T08:15:59.000Z", "Asia/Colombo"],
result: "2021-03-14T13:45:59.000+0530",
},
{
desc: "UTC to Asia/Colombo (2)",
desc: "ISO+Offset to Asia/Colombo (2)",
inputs: ["2021-03-14T13:45:59.000+0530", "Asia/Colombo"],
result: "2021-03-14T13:45:59.000+0530",
},
{
desc: "UTC to Asia/Colombo (3)",
desc: "UTC Zulu to Asia/Colombo (3)",
inputs: ["2021-11-07T08:15:59.000Z", "Asia/Colombo"],
result: "2021-11-07T13:45:59.000+0530",
},
{
desc: "UTC to Asia/Colombo (4)",
desc: "ISO+Offset to Asia/Colombo (4)",
inputs: ["2021-11-07T13:45:59.000+0530", "Asia/Colombo"],
result: "2021-11-07T13:45:59.000+0530",
},
].forEach(testUtcToTz);
console.info("Pass: UTC to TZ for America/New_York and Asia/Colombo");
console.info(
"Pass: UTC/ISO+Offset to TZ for America/New_York and Asia/Colombo"
);
[
//

49
xtz.js
View File

@ -1,6 +1,4 @@
var XTZ;
(function () {
(function (exports) {
"use strict";
function toTimeZone(date, timeZone) {
@ -62,15 +60,16 @@ var XTZ;
function toTimeZoneISOString(date, timeZone) {
var whole = toTimeZone(date, timeZone);
return toOffsetISOString(whole);
return formatAsOffsetISOString(whole);
}
function _toOffsetISOString() {
return toOffsetISOString(this);
/* jshint validthis: true */
return formatAsOffsetISOString(this);
}
function getOffset(utcDate, tzD2) {
var tzDate = new Date(toOffsetISOString(tzD2));
var tzDate = new Date(formatAsOffsetISOString(tzD2));
var diff = Math.round((tzDate.valueOf() - utcDate.valueOf()) / (60 * 1000));
return diff;
}
@ -98,10 +97,21 @@ var XTZ;
}
// +0500, -0730
return offset + p2(h) + p2(m);
return (
offset + h.toString().padStart(2, "0") + m.toString().padStart(2, "0")
);
}
function toOffsetISOString(d) {
function toOffsetISOString(date, timeZone) {
if ("offset" in date && "year" in date) {
return formatAsOffsetISOString(date);
}
var whole = fromTimeZone(date, timeZone);
return formatAsOffsetISOString(whole);
}
function formatAsOffsetISOString(d) {
var offset = formatOffset(d.offset);
return (
`${d.year}-${p2(d.month + 1)}-${p2(d.day)}` +
@ -111,7 +121,7 @@ var XTZ;
);
}
function toUTC(dt, tz) {
function fromTimeZone(dt, tz) {
if ("string" === typeof dt) {
// Either of these formats should work:
// 2021-03-14 01:15:59
@ -148,11 +158,6 @@ var XTZ;
return tzD3;
}
function toUTCISOString(date, timeZone) {
var whole = toUTC(date, timeZone);
return toOffsetISOString(whole);
}
function toLocalISOString(dateOrStr) {
var d;
if (dateOrStr) {
@ -174,15 +179,17 @@ var XTZ;
return `${YYYY}-${MM}-${DD}T${hh}:${mm}:${ss}.${sss}${offset}`;
}
XTZ = {
exports.XTZ = {
// bespoke date =>
// 2021-11-07T3:15:59-0500
// (todo?)
// xtzToISOString: formatAsOffsetISOString,
// (deprecated)
toOffsetISOString: toOffsetISOString,
// -240 => -0400
formatOffset: formatOffset,
// new Date() => "2021-11-07T03:15:59-0500"
toLocalISOString: toLocalISOString,
// [ "2021-11-07T08:15:59Z", "America/New_York" ]
@ -192,11 +199,13 @@ var XTZ;
// [ "2021-11-07 03:15:59", "America/New_York" ]
// => "2021-11-07T03:15:59-0500" // 2021-11-07T08:15:59Z
toUTC: toUTC,
toUTCISOString: toUTCISOString,
toUTC: fromTimeZone,
fromTimeZone: fromTimeZone,
// deprecated
toUTCISOString: toOffsetISOString,
};
if ("undefined" != typeof module && module.exports) {
module.exports = XTZ;
module.exports = exports.XTZ;
}
})();
})(("undefined" === typeof module && window) || exports);