From c30ecbd127ffdef4e7d2790d882855de94aa6ea3 Mon Sep 17 00:00:00 2001 From: AJ ONeal Date: Thu, 27 May 2021 15:05:02 -0600 Subject: [PATCH] UTC => TZ conversion works --- index.js | 147 ++++++++++++++++++++++++++------ test.js | 254 +++++++++++++++++++++++++++++-------------------------- 2 files changed, 256 insertions(+), 145 deletions(-) diff --git a/index.js b/index.js index 7fa72c9..5fbb3ad 100644 --- a/index.js +++ b/index.js @@ -1,27 +1,126 @@ -/** - * take a date of assumed timezone and convert to utc - * - * @param {*} d - * @param {*} tz - * @returns - */ -function tzUTC(d, tz) { - // first calculate tz difference - var date = new Date(); +"use strict"; + +function fromUTCToTimeZone(date, timeZone) { + // ISO string or existing date object + date = new Date(date); var options = { - year: 'numeric', - month: 'numeric', - day: 'numeric', - hour: 'numeric', - minute: 'numeric', - second: 'numeric', + timeZone: timeZone, + year: "numeric", + month: "numeric", + day: "numeric", 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 minutes = Math.floor((diff / 1000) / 60); - var localTime = new Date(d); - localTime.setMinutes(d.getMinutes() + minutes); - return localTime.toUTCString(); -} \ No newline at end of file + + var tzOptions = Object.assign( + { + timeZoneName: "long", + }, + 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, +}; diff --git a/test.js b/test.js index e08b0ff..7afce5f 100644 --- a/test.js +++ b/test.js @@ -1,133 +1,145 @@ -var d = new Date("5/18/2019, 07:49:13"); -// 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')) +"use strict"; -d = new Date("5/17/2019, 14:53:21"); -console.log("d:" + d) +var TZ = require("./"); -// Fri May 17 2019 17:53:21 GMT-0400 (Eastern Daylight Time) -// utc "Fri, 17 May 2019 21:53:21 GMT" +// At this real UTC time, what does the timezone translate it to? +[ + // + // 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", + }, -////// -////// 9:01 twice -////// + // NOTE: Can't 2:15am NY, because it does not exist (skipped by DST) -var d = new Date("3/10/2019, 01:59:00"); -console.log("tzUTC:" + tzUTC(d, 'America/Denver')); -// tzUTC:Sun, 10 Mar 2019 08:59:00 GMT + // 3:15am NY (DST) + { + 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')); -// tzUTC:Sun, 10 Mar 2019 09:01:00 GMT + // + // End-of-DST Tests + // -var d = new Date("3/10/2019, 02:59:00"); -console.log("tzUTC:" + tzUTC(d, 'America/Denver')); -// tzUTC:Sun, 10 Mar 2019 09:59:00 GMT + // [Start] + // What time is '2021-11-07 01:15:59.000 in New York' in UTC? // 2021-11-07 05:15:59.000 + // // 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"); -console.log("tzUTC:" + tzUTC(d, 'America/Denver')); -// tzUTC:Sun, 10 Mar 2019 09:01:00 GMT + // 12:15am NY -0400 => -0500 + { + 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"); -console.log("tzUTC:" + tzUTC(d, 'America/Denver')); -// tzUTC:Sun, 03 Nov 2019 07:59:00 GMT - -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 - -var d = new Date("11/03/2019, 02:59:00"); -console.log("tzUTC:" + tzUTC(d, 'America/Denver')); -// tzUTC:Sun, 03 Nov 2019 09:59:00 GMT - -var d = new Date("11/03/2019, 03:01:00"); -console.log("tzUTC:" + tzUTC(d, 'America/Denver')); -tzUTC:Sun, 03 Nov 2019 10:01:00 GMT - - -/* -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 + // 4:15am Colombo +0530 (not DST) + { + inputs: ["2021-03-14T08:15:59.000Z", "Asia/Colombo"], + result: "2021-03-14T13:45:59.000+0530", + }, + { + inputs: ["2021-03-14T13:45:59.000+0530", "Asia/Colombo"], + result: "2021-03-14T13:45:59.000+0530", + }, +].forEach(function (t) { + var result = TZ.fromUTCToTimeZone.apply(TZ, t.inputs).toISOString(); + if (t.result !== result) { + throw new Error( + "Invalid Conversion:\n" + + `\tExpected: ${t.result}\n` + + `\tActual: ${result}\n` + ); } - ]; - - 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)); \ No newline at end of file +});