<p dir="auto">I18n is essetial i think so:<br>
ICU/Intl is require but there is a problem in JS word to using i18n:</p>
<ul dir="auto">
<li>There is no valid implementation ISO for Intl. It's wired implementation for JS.</li>
<li>It's not the entire ICU library it's just simple the implementation that not cover all use cases.</li>
<li>There is no parser for Convert none Georgian calendar to Standard Unix time or Standard Date Object. and etc.</li>
<li>Access standard CLDR data (json output: <a href="https://github.com/unicode-cldr/cldr-json">https://github.com/unicode-cldr/cldr-json</a>). List of valid locales and currency/calendar and etc ...specs... why it's not essential part of JS core ? I donno !!!</li>
</ul>
<p dir="auto"><a href="https://stackoverflow.com/questions/29961992/javascript-intl-datetimeformatter-as-iso-8601custom-output-pattern" rel="nofollow">https://stackoverflow.com/questions/29961992/javascript-intl-datetimeformatter-as-iso-8601custom-output-pattern</a><br>
<a href="https://medium.com/@semnanweb/javascript-intl-fails-da3cda114370" rel="nofollow">https://medium.com/@semnanweb/javascript-intl-fails-da3cda114370</a></p>
<p dir="auto">I suggest to see PHP implementation instead of Using same problem for JS<br>
<a href="https://www.php.net/manual/en/book.intl.php" rel="nofollow">https://www.php.net/manual/en/book.intl.php</a><br>
C library:<br>
<a href="https://unicode-org.github.io/icu-docs/apidoc/released/icu4c/" rel="nofollow">https://unicode-org.github.io/icu-docs/apidoc/released/icu4c/</a><br>
CLDR data:<br>
<a href="http://cldr.unicode.org/" rel="nofollow">http://cldr.unicode.org/</a></p>
<p dir="auto">As seen in <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="422116599" data-permission-text="Title is private" data-url="https://github.com/denoland/deno/issues/1952" data-hovercard-type="issue" data-hovercard-url="/denoland/deno/issues/1952/hovercard" href="https://github.com/denoland/deno/issues/1952">#1952</a> / <a class="issue-link js-issue-link" data-error-text="Failed to load title" data-id="405562913" data-permission-text="Title is private" data-url="https://github.com/denoland/deno/issues/1636" data-hovercard-type="issue" data-hovercard-url="/denoland/deno/issues/1636/hovercard" href="https://github.com/denoland/deno/issues/1636">#1636</a> ICU needs to be added in Deno build.</p>
<p dir="auto">Switching this flag to true maybe: <a href="https://github.com/denoland/deno/blob/master/.gn#L50">https://github.com/denoland/deno/blob/master/.gn#L50</a> ?</p>
<p dir="auto">ref: <a href="https://v8.dev/docs/i18n" rel="nofollow">https://v8.dev/docs/i18n</a></p>