How to get first day of the week in user region?

[pie6k]

Some countries use Sunday, Monday, or even other days http://chartsbin.com/view/41671

Is it possible to get it using this lib?

[zoontek]

@pie6k Hi. Totally, yes (even if it's not supported yet). If we refer to http://cldr.unicode.org latest release, we found in supplementalData.xml these infos:

<firstDay day="mon" territories="001 AD AI AL AM AN AR AT AX AZ BA BE BG BM BN BY CH CL CM CR CY CZ DE DK EC EE ES FI FJ FO FR GB GE GF GP GR HR HU IE IS IT KG KZ LB LI LK LT LU LV MC MD ME MK MN MQ MY NL NO NZ PL RE RO RS RU SE SI SK SM TJ TM TR UA UY UZ VA VN XK" />
<firstDay day="fri" territories="MV" />
<firstDay day="sat" territories="AE AF BH DJ DZ EG IQ IR JO KW LY OM QA SD SY" />
<firstDay day="sun" territories="AG AS AU BD BR BS BT BW BZ CA CN CO DM DO ET GB GT GU HK HN ID IL IN JM JP KE KH KR LA MH MM MO MT MX MZ NI NP PA PE PH PK PR PT PY SA SG SV TH TT TW UM US VE VI WS YE ZA ZW" />

As 001 means regions not explicitly listed, we can simplify it to:

import { getCountry } from "react-native-localize";

const startsOnFriday = ["MV"];

const startsOnSaturday = [
  "AE",
  "AF",
  "BH",
  "DJ",
  "DZ",
  "EG",
  "IQ",
  "IR",
  "JO",
  "KW",
  "LY",
  "OM",
  "QA",
  "SD",
  "SY",
];

const startsOnSunday = [
  "AG",
  "AS",
  "AU",
  "BD",
  "BR",
  "BS",
  "BT",
  "BW",
  "BZ",
  "CA",
  "CN",
  "CO",
  "DM",
  "DO",
  "ET",
  "GB",
  "GT",
  "GU",
  "HK",
  "HN",
  "ID",
  "IL",
  "IN",
  "JM",
  "JP",
  "KE",
  "KH",
  "KR",
  "LA",
  "MH",
  "MM",
  "MO",
  "MT",
  "MX",
  "MZ",
  "NI",
  "NP",
  "PA",
  "PE",
  "PH",
  "PK",
  "PR",
  "PT",
  "PY",
  "SA",
  "SG",
  "SV",
  "TH",
  "TT",
  "TW",
  "UM",
  "US",
  "VE",
  "VI",
  "WS",
  "YE",
  "ZA",
  "ZW",
];

function getFirstDayOfWeek() {
  const country = getCountry();

  if (startsOnFriday.includes(country)) {
    return "friday";
  }
  if (startsOnSaturday.includes(country)) {
    return "saturday";
  }
  if (startsOnSunday.includes(country)) {
    return "sunday";
  }

  return "monday";
}

A bit roots but it's works! Might seems fat but is actually only 653 bytes minified (without gzip) 🙂

[MoOx]

I am interested to have this too :)

[robrechtme]

On iOS there's now a separate setting for this, so looking at the country won't always be correct. Is there a way to expose this setting? 🙂

[zoontek]

@robrechtme There is indeed room for a new feature here (with fallback to the list above)

[tinkench]

@zoontek Two countries have changed they first day of the week since your comment. Here is the updated version:

import { getCountry } from "react-native-localize";

const startsOnFriday = ["MV"];

const startsOnSaturday = [
  "AE",
  "AF",
  "BH",
  "DJ",
  "DZ",
  "EG",
  "IQ",
  "IR",
  "JO",
  "KW",
  "LY",
  "OM",
  "QA",
  "SD",
  "SY",
];

const startsOnSunday = [
  "AG",
  "AS",
  "BD",
  "BR",
  "BS",
  "BT",
  "BW",
  "BZ",
  "CA",
  "CO",
  "DM",
  "DO",
  "ET",
  "GB",
  "GT",
  "GU",
  "HK",
  "HN",
  "ID",
  "IL",
  "IN",
  "JM",
  "JP",
  "KE",
  "KH",
  "KR",
  "LA",
  "MH",
  "MM",
  "MO",
  "MT",
  "MX",
  "MZ",
  "NI",
  "NP",
  "PA",
  "PE",
  "PH",
  "PK",
  "PR",
  "PT",
  "PY",
  "SA",
  "SG",
  "SV",
  "TH",
  "TT",
  "TW",
  "UM",
  "US",
  "VE",
  "VI",
  "WS",
  "YE",
  "ZA",
  "ZW",
];

function getFirstDayOfWeek() {
  const country = getCountry();

  if (startsOnFriday.includes(country)) {
    return "friday";
  }
  if (startsOnSaturday.includes(country)) {
    return "saturday";
  }
  if (startsOnSunday.includes(country)) {
    return "sunday";
  }

  return "monday";
}

[chenei]

@zoontek sorry for bringing this up, there is a new option on iOS to choose whatever first day of the week you want, is there a way you support that?