luxon
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Immutable date wrapper
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<title data-ice="title">Luxon</title>
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<header><span class="luxon-title">Luxon</span>
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<div data-ice="manual" data-toc-name="design">
<ul class="manual-toc">
<li data-ice="manualNav" class="indent-h1 manual-color manual-color-design" data-section-count="■■" data-link="manual/design/install.html"><a href="manual/design/install.html" data-ice="link">Install guide</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/design/install.html"><a href="manual/design/install.html#basic-browser-setup" data-ice="link">Basic browser setup</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/design/install.html"><a href="manual/design/install.html#node" data-ice="link">Node</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/design/install.html"><a href="manual/design/install.html#amd-system-js-requirejs-etc-" data-ice="link">AMD (System.js, RequireJS, etc)</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/design/install.html"><a href="manual/design/install.html#es6" data-ice="link">ES6</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/design/install.html"><a href="manual/design/install.html#webpack" data-ice="link">Webpack</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/design/install.html"><a href="manual/design/install.html#meteor" data-ice="link">Meteor</a></li>
<li data-ice="manualNav" class="indent-h1 manual-color manual-color-design" data-section-count="■■■■" data-link="manual/design/tour.html"><a href="manual/design/tour.html" data-ice="link">A quick tour</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/design/tour.html"><a href="manual/design/tour.html#your-first-datetime" data-ice="link">Your first DateTime</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/design/tour.html"><a href="manual/design/tour.html#creating-a-datetime" data-ice="link">Creating a DateTime</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/design/tour.html"><a href="manual/design/tour.html#create-from-an-object" data-ice="link">Create from an object</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/design/tour.html"><a href="manual/design/tour.html#parse-from-iso-8601" data-ice="link">Parse from ISO 8601</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/design/tour.html"><a href="manual/design/tour.html#getting-to-know-your-datetime-instance" data-ice="link">Getting to know your DateTime instance</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/design/tour.html"><a href="manual/design/tour.html#tostring" data-ice="link">toString</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/design/tour.html"><a href="manual/design/tour.html#getting-at-components" data-ice="link">Getting at components</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/design/tour.html"><a href="manual/design/tour.html#other-fun-accessors" data-ice="link">Other fun accessors</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/design/tour.html"><a href="manual/design/tour.html#formatting-your-datetime" data-ice="link">Formatting your DateTime</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/design/tour.html"><a href="manual/design/tour.html#transforming-your-datetime" data-ice="link">Transforming your DateTime</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/design/tour.html"><a href="manual/design/tour.html#immutability" data-ice="link">Immutability</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/design/tour.html"><a href="manual/design/tour.html#math" data-ice="link">Math</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/design/tour.html"><a href="manual/design/tour.html#set" data-ice="link">Set</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/design/tour.html"><a href="manual/design/tour.html#intl" data-ice="link">Intl</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/design/tour.html"><a href="manual/design/tour.html#time-zones" data-ice="link">Time zones</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/design/tour.html"><a href="manual/design/tour.html#durations" data-ice="link">Durations</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/design/tour.html"><a href="manual/design/tour.html#intervals" data-ice="link">Intervals</a></li>
</ul>
</div>
<div data-ice="manual" data-toc-name="usage">
<ul class="manual-toc">
<li data-ice="manualNav" class="indent-h1 manual-color manual-color-usage" data-section-count="■■" data-link="manual/usage/intl.html"><a href="manual/usage/intl.html" data-ice="link">Intl</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/intl.html"><a href="manual/usage/intl.html#how-locales-work" data-ice="link">How locales work</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/intl.html"><a href="manual/usage/intl.html#setting-locale" data-ice="link">Setting locale</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/intl.html"><a href="manual/usage/intl.html#checking-what-you-got" data-ice="link">Checking what you got</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/intl.html"><a href="manual/usage/intl.html#methods-affected-by-the-locale" data-ice="link">Methods affected by the locale</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/intl.html"><a href="manual/usage/intl.html#formatting" data-ice="link">Formatting</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/intl.html"><a href="manual/usage/intl.html#parsing" data-ice="link">Parsing</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/intl.html"><a href="manual/usage/intl.html#listing" data-ice="link">Listing</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/intl.html"><a href="manual/usage/intl.html#numberingsystem" data-ice="link">numberingSystem</a></li>
<li data-ice="manualNav" class="indent-h1 manual-color manual-color-usage" data-section-count="■■■■■" data-link="manual/usage/zones.html"><a href="manual/usage/zones.html" data-ice="link">Time zones and offsets</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/zones.html"><a href="manual/usage/zones.html#don-t-worry-" data-ice="link">Don't worry!</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/zones.html"><a href="manual/usage/zones.html#terminology" data-ice="link">Terminology</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/zones.html"><a href="manual/usage/zones.html#luxon-works-with-time-zones" data-ice="link">Luxon works with time zones</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/zones.html"><a href="manual/usage/zones.html#specifying-a-zone" data-ice="link">Specifying a zone</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/zones.html"><a href="manual/usage/zones.html#iana-support" data-ice="link">IANA support</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/zones.html"><a href="manual/usage/zones.html#creating-datetimes" data-ice="link">Creating DateTimes</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/zones.html"><a href="manual/usage/zones.html#local-by-default" data-ice="link">Local by default</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/zones.html"><a href="manual/usage/zones.html#creating-datetimes-in-a-zone" data-ice="link">Creating DateTimes in a zone</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/zones.html"><a href="manual/usage/zones.html#strings-that-specify-an-offset" data-ice="link">Strings that specify an offset</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/zones.html"><a href="manual/usage/zones.html#setzone" data-ice="link">setZone</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/zones.html"><a href="manual/usage/zones.html#changing-zones" data-ice="link">Changing zones</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/zones.html"><a href="manual/usage/zones.html#setzone" data-ice="link">setZone</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/zones.html"><a href="manual/usage/zones.html#keepcalendartime" data-ice="link">keepCalendarTime</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/zones.html"><a href="manual/usage/zones.html#accessors" data-ice="link">Accessors</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/zones.html"><a href="manual/usage/zones.html#dst-weirdness" data-ice="link">DST weirdness</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/zones.html"><a href="manual/usage/zones.html#invalid-times" data-ice="link">Invalid times</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/zones.html"><a href="manual/usage/zones.html#ambiguous-times" data-ice="link">Ambiguous times</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/zones.html"><a href="manual/usage/zones.html#math-across-dsts" data-ice="link">Math across DSTs</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/zones.html"><a href="manual/usage/zones.html#changing-the-default-zone" data-ice="link">Changing the default zone</a></li>
<li data-ice="manualNav" class="indent-h1 manual-color manual-color-usage" data-section-count="■" data-link="manual/usage/calendars.html"><a href="manual/usage/calendars.html" data-ice="link">Calendars</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/calendars.html"><a href="manual/usage/calendars.html#fully-supported-calendars" data-ice="link">Fully supported calendars</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/calendars.html"><a href="manual/usage/calendars.html#output-calendars" data-ice="link">Output calendars</a></li>
<li data-ice="manualNav" class="indent-h1 manual-color manual-color-usage" data-section-count="■■■■" data-link="manual/usage/formatting.html"><a href="manual/usage/formatting.html" data-ice="link">Formatting</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/formatting.html"><a href="manual/usage/formatting.html#technical-formats-strings-for-computers-" data-ice="link">Technical formats (strings for computers)</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/formatting.html"><a href="manual/usage/formatting.html#iso-8601" data-ice="link">ISO 8601</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/formatting.html"><a href="manual/usage/formatting.html#http-and-rfc-2822" data-ice="link">HTTP and RFC 2822</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/formatting.html"><a href="manual/usage/formatting.html#tolocalestring-strings-for-humans-" data-ice="link">toLocaleString (strings for humans)</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/formatting.html"><a href="manual/usage/formatting.html#the-basics" data-ice="link">The basics</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/formatting.html"><a href="manual/usage/formatting.html#intl-datetimeformat" data-ice="link">Intl.DateTimeFormat</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/formatting.html"><a href="manual/usage/formatting.html#presets" data-ice="link">Presets</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/formatting.html"><a href="manual/usage/formatting.html#intl" data-ice="link">Intl</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/formatting.html"><a href="manual/usage/formatting.html#formatting-with-tokens-strings-for-cthulhu-" data-ice="link">Formatting with tokens (strings for Cthulhu)</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/formatting.html"><a href="manual/usage/formatting.html#consider-alternatives" data-ice="link">Consider alternatives</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/formatting.html"><a href="manual/usage/formatting.html#toformat" data-ice="link">toFormat</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/formatting.html"><a href="manual/usage/formatting.html#intl" data-ice="link">Intl</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/formatting.html"><a href="manual/usage/formatting.html#escaping" data-ice="link">Escaping</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/formatting.html"><a href="manual/usage/formatting.html#standalone-vs-format-tokens" data-ice="link">Standalone vs format tokens</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/formatting.html"><a href="manual/usage/formatting.html#macro-tokens" data-ice="link">Macro tokens</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/formatting.html"><a href="manual/usage/formatting.html#table-of-tokens" data-ice="link">Table of tokens</a></li>
<li data-ice="manualNav" class="indent-h1 manual-color manual-color-usage" data-section-count="■■■" data-link="manual/usage/parsing.html"><a href="manual/usage/parsing.html" data-ice="link">Parsing</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/parsing.html"><a href="manual/usage/parsing.html#parsing-technical-formats" data-ice="link">Parsing technical formats</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/parsing.html"><a href="manual/usage/parsing.html#iso-8601" data-ice="link">ISO 8601</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/parsing.html"><a href="manual/usage/parsing.html#http-and-rfc2822" data-ice="link">HTTP and RFC2822</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/parsing.html"><a href="manual/usage/parsing.html#ad-hoc-parsing" data-ice="link">Ad-hoc parsing</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/parsing.html"><a href="manual/usage/parsing.html#consider-alternatives" data-ice="link">Consider alternatives</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/parsing.html"><a href="manual/usage/parsing.html#fromstring" data-ice="link">fromString</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/parsing.html"><a href="manual/usage/parsing.html#intl" data-ice="link">Intl</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/parsing.html"><a href="manual/usage/parsing.html#limitations" data-ice="link">Limitations</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/parsing.html"><a href="manual/usage/parsing.html#debugging" data-ice="link">Debugging</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/parsing.html"><a href="manual/usage/parsing.html#table-of-tokens" data-ice="link">Table of tokens</a></li>
<li data-ice="manualNav" class="indent-h1 manual-color manual-color-usage" data-section-count="■■■" data-link="manual/usage/math.html"><a href="manual/usage/math.html" data-ice="link">Math</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/math.html"><a href="manual/usage/math.html#calendar-math-vs-time-math" data-ice="link">Calendar math vs time math</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/math.html"><a href="manual/usage/math.html#the-basics" data-ice="link">The basics</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/math.html"><a href="manual/usage/math.html#which-units-use-which-math-" data-ice="link">Which units use which math?</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/math.html"><a href="manual/usage/math.html#how-to-think-about-calendar-math" data-ice="link">How to think about calendar math</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/math.html"><a href="manual/usage/math.html#dsts" data-ice="link">DSTs</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/math.html"><a href="manual/usage/math.html#time-math" data-ice="link">Time math</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/math.html"><a href="manual/usage/math.html#math-with-multiple-units" data-ice="link">Math with multiple units</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/math.html"><a href="manual/usage/math.html#duration-math" data-ice="link">Duration math</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/math.html"><a href="manual/usage/math.html#basics" data-ice="link">Basics</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/math.html"><a href="manual/usage/math.html#diffs" data-ice="link">Diffs</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/math.html"><a href="manual/usage/math.html#casual-vs-longterm-conversion-accuracy" data-ice="link">Casual vs longterm conversion accuracy</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/math.html"><a href="manual/usage/math.html#losing-information" data-ice="link">Losing information</a></li>
<li data-ice="manualNav" class="indent-h1 manual-color manual-color-usage" data-section-count="■■" data-link="manual/usage/validity.html"><a href="manual/usage/validity.html" data-ice="link">Validity</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/validity.html"><a href="manual/usage/validity.html#invalid-datetimes" data-ice="link">Invalid DateTimes</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/validity.html"><a href="manual/usage/validity.html#reasons-a-datetimes-can-be-invalid" data-ice="link">Reasons a DateTimes can be invalid</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/validity.html"><a href="manual/usage/validity.html#debugging-invalid-datetimes" data-ice="link">Debugging invalid DateTimes</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/validity.html"><a href="manual/usage/validity.html#invalidreason" data-ice="link">invalidReason</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/usage/validity.html"><a href="manual/usage/validity.html#throwoninvalid" data-ice="link">throwOnInvalid</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/validity.html"><a href="manual/usage/validity.html#invalid-durations" data-ice="link">Invalid Durations</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/usage/validity.html"><a href="manual/usage/validity.html#invalid-intervals" data-ice="link">Invalid Intervals</a></li>
</ul>
</div>
<div data-ice="manual" data-toc-name="reference">
<ul class="manual-toc">
<li data-ice="manualNav" class="indent-h1 manual-color manual-color-reference" data-section-count="■■" data-link="identifiers.html"><a href="identifiers.html" data-ice="link">API reference</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="identifiers.html"><a href="identifiers.html#class" data-ice="link">Class</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="identifiers.html"><a href="identifiers.html#interface" data-ice="link">Interface</a></li>
</ul>
</div>
<div data-ice="manual" data-toc-name="faq">
<ul class="manual-toc">
<li data-ice="manualNav" class="indent-h1 manual-color manual-color-faq" data-section-count="■■" data-link="manual/faq/matrix.html"><a href="manual/faq/matrix.html" data-ice="link">Support matrix</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/faq/matrix.html"><a href="manual/faq/matrix.html#what-works-everywhere" data-ice="link">What works everywhere</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/faq/matrix.html"><a href="manual/faq/matrix.html#new-capabilities-and-how-they-re-used" data-ice="link">New capabilities and how they're used</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/faq/matrix.html"><a href="manual/faq/matrix.html#the-matrix" data-ice="link">The matrix</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/faq/matrix.html"><a href="manual/faq/matrix.html#what-happens-if-a-feature-isn-t-supported-" data-ice="link">What happens if a feature isn't supported?</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/faq/matrix.html"><a href="manual/faq/matrix.html#polyfills" data-ice="link">Polyfills</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/faq/matrix.html"><a href="manual/faq/matrix.html#intl" data-ice="link">Intl</a></li>
<li data-ice="manualNav" class="indent-h3" data-link="manual/faq/matrix.html"><a href="manual/faq/matrix.html#zones" data-ice="link">Zones</a></li>
<li data-ice="manualNav" class="indent-h1 manual-color manual-color-faq" data-section-count="■■■■" data-link="manual/faq/moment.html"><a href="manual/faq/moment.html" data-ice="link">For Moment users</a></li>
<li data-ice="manualNav" class="indent-h2" data-link="manual/faq/moment.html"><a href="manual/faq/moment.html#immutability" data-ice="link">Immutability</a></li>
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<span data-ice="title">Usage</span>
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<div data-ice="content"><h1 id="validity">Validity</h1>
<h2 id="invalid-datetimes">Invalid DateTimes</h2>
<p>One of the most irritating aspects of programming with time is that it's possible to end up with invalid dates. This is a bit subtle: barring integer overflows, there's no count of milliseconds that don't correspond to a valid DateTime, but when working with calendar units, it's pretty easy to say something like "June 400th". Luxon considers that invalid and will mark it accordingly.</p>
<p>Unless if you've asked Luxon to throw an exception when it creates an invalid DateTime (see more on that below), it will fail silently, creating an instance that doesn't know how to do anything. You can check validity with <code>isValid</code>:</p>
<pre><code class="lang-js"><code class="source-code prettyprint">> var dt = DateTime.fromObject({ month: 6, day: 400 });
dt.isValid //=> false</code>
</code></pre>
<p>All of the methods or getters that return primitives return degenerate ones:</p>
<pre><code class="lang-js"><code class="source-code prettyprint">dt.year; //=> NaN
dt.toString(); //=> 'Invalid DateTime'
dt.toObject(); //=> {}</code>
</code></pre>
<p>Methods that return other Luxon objects will return invalid ones:</p>
<pre><code class="lang-js"><code class="source-code prettyprint">dt.plus({ days: 4 }).isValid; //=> false</code>
</code></pre>
<h2 id="reasons-a-datetimes-can-be-invalid">Reasons a DateTimes can be invalid</h2>
<p>The most common way to do that is to over or underflow some unit:</p>
<ul>
<li>February 40th</li>
<li>28:00</li>
<li>-4 pm</li>
<li>etc</li>
</ul>
<p>But there are other ways to do it:</p>
<pre><code class="lang-js"><code class="source-code prettyprint">// specify a time zone that doesn't exist
DateTime.local().setZone('America/Blorp').isValid //=> false
// provide contradictory information (here, this date is not a Wedensday)
DateTime.fromObject({ year: 2017, month: 5, day: 25, weekday: 3}).isValid //=> false</code>
</code></pre>
<p>Note that some other kinds of mistakes throw, based on our judgment that they are more likely programmer errors than data issues:</p>
<pre><code class="lang-js"><code class="source-code prettyprint">DateTime.local().set({ blorp: 7 }); //=> kerplosion</code>
</code></pre>
<h2 id="debugging-invalid-datetimes">Debugging invalid DateTimes</h2>
<p>Because DateTimes fail silently, they can be a pain to debug. There are two features that can help.</p>
<h3 id="invalidreason">invalidReason</h3>
<p>Invalid DateTime objects are happy to tell you why they're invalid. Like this:</p>
<pre><code class="lang-js"><code class="source-code prettyprint">DateTime.local().setZone('America/Blorp').invalidReason; //=> 'unsupported zone'</code>
</code></pre>
<h3 id="throwoninvalid">throwOnInvalid</h3>
<p>You can make Luxon throw whenever it creates an invalid DateTime.</p>
<pre><code class="lang-js"><code class="source-code prettyprint">Settings.throwOnInvalid = true
DateTime.local().setZone('America/Blorp'); // Error: Invalid DateTime: unsupported zone</code>
</code></pre>
<p>You can of course leave this on in production too, but be sure to try/catch it appropriately.</p>
<h2 id="invalid-durations">Invalid Durations</h2>
<p>Durations can be invalid too. The easiest way to get one is to diff an invalid DateTime. </p>
<pre><code class="lang-js"><code class="source-code prettyprint">DateTime.local(2017, 28).diffNow().isValid //=> false</code>
</code></pre>
<h2 id="invalid-intervals">Invalid Intervals</h2>
<p>Intervals can be invalid. This can happen a few different ways:</p>
<ul>
<li>The end time is before the start time</li>
<li>It was created from invalid DateTime or Duration</li>
</ul>
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