Add Format Time Zone Identifier as a JavaScript TIL

README.md

@@ -10,7 +10,7 @@ pairing with smart people at Hashrocket.
 
 For a steady stream of TILs, [sign up for my newsletter](https://crafty-builder-6996.ck.page/e169c61186).
 
-_1427 TILs and counting..._
+_1428 TILs and counting..._
 
 ---
 
@@ -462,6 +462,7 @@ _1427 TILs and counting..._
 - [Find Where Yarn Is Installing Binaries](javascript/find-where-yarn-is-installing-binaries.md)
 - [for...in Iterates Over Object Properties](javascript/for-in-iterates-over-object-properties.md)
 - [Format A Decimal To A Fixed Number Of Digits](javascript/format-a-decimal-to-a-fixed-number-of-digits.md)
+- [Format Time Zone Identifier](javascript/format-time-zone-identifier.md)
 - [Formatting Values With Units For Display](javascript/formatting-values-with-units-for-display.md)
 - [Freeze An Object, Sorta](javascript/freeze-an-object-sorta.md)
 - [Generate A V4 UUID In The Browser](javascript/generate-a-v4-uuid-in-the-browser.md)

javascript/format-time-zone-identifier.md

@@ -0,0 +1,34 @@
+# Format Time Zone Identifier
+
+Though there are surely libraries that can help with this task, we now have
+full support in the [`Intl.DateTimeFormat`
+API](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/DateTimeFormat/DateTimeFormat)
+for formatting a date's time zone identifier in various ways.
+
+To do this, we have to create a formatter specifying the locale, the `timeZone`
+option, and any formatting options. For the formatting, I'll try the
+`timeZoneName` with both `short` and `longGeneric`.
+
+Then we `formatToParts` on any date object and extract the `timeZoneName`
+value:
+
+```javascript
+const options = { timeZone: 'America/Chicago', timeZoneName: "short" }
+const formatter = new Intl.DateTimeFormat("en-US", options)
+
+formatter.formatToParts(new Date()).find((part) => part.type === "timeZoneName").value
+//=> 'CDT'
+```
+
+Now, let's try this for `longGeneric`:
+
+```javascript
+const options = { timeZone: 'America/Chicago', timeZoneName: "longGeneric" }
+const formatter = new Intl.DateTimeFormat("en-US", options)
+
+formatter.formatToParts(new Date()).find((part) => part.type === "timeZoneName").value
+//=> 'Central Time'
+```
+
+There are several more options for the `timeZoneName` as well as a bunch more
+you can do with the `Intl.DateTimeFormat` API.