From b741194b7d38fa2e83370b217c6cd5448960e03a Mon Sep 17 00:00:00 2001
From: mike12345567 <me@michaeldrury.co.uk>
Date: Wed, 9 Jun 2021 11:44:24 +0100
Subject: [PATCH] Updating date helper to allow timezone capabilites.

---
 packages/string-templates/src/helpers/date.js | 14 ++++++++++++--
 .../string-templates/test/helpers.spec.js     | 19 +++++++++++++++++++
 2 files changed, 31 insertions(+), 2 deletions(-)

diff --git a/packages/string-templates/src/helpers/date.js b/packages/string-templates/src/helpers/date.js
index ce845eee3f..440657b733 100644
--- a/packages/string-templates/src/helpers/date.js
+++ b/packages/string-templates/src/helpers/date.js
@@ -3,6 +3,7 @@ dayjs.extend(require("dayjs/plugin/duration"))
 dayjs.extend(require("dayjs/plugin/advancedFormat"))
 dayjs.extend(require("dayjs/plugin/relativeTime"))
 dayjs.extend(require("dayjs/plugin/utc"))
+dayjs.extend(require("dayjs/plugin/timezone"))
 
 /**
  * This file was largely taken from the helper-date package - we did this for two reasons:
@@ -72,7 +73,8 @@ function setLocale(str, pattern, options) {
   // if options is null then it'll get updated here
   const config = initialConfig(str, pattern, options)
   const defaults = { lang: "en", date: new Date(config.str) }
-  const opts = getContext(this, defaults, config.options)
+  // for now don't allow this to be configurable, don't pass in options
+  const opts = getContext(this, defaults, {})
 
   // set the language to use
   dayjs.locale(opts.lang || opts.language)
@@ -89,7 +91,15 @@ module.exports.date = (str, pattern, options) => {
 
   setLocale(config.str, config.pattern, config.options)
 
-  const date = dayjs(new Date(config.str)).utc()
+  let date = dayjs(new Date(config.str))
+  if (typeof config.options === "string") {
+    date =
+      config.options.toLowerCase() === "utc"
+        ? date.utc()
+        : date.tz(config.options)
+  } else {
+    date = date.tz(dayjs.tz.guess())
+  }
   if (config.pattern === "") {
     return date.toISOString()
   }
diff --git a/packages/string-templates/test/helpers.spec.js b/packages/string-templates/test/helpers.spec.js
index 6be8e2ed0e..f0a71b9ba4 100644
--- a/packages/string-templates/test/helpers.spec.js
+++ b/packages/string-templates/test/helpers.spec.js
@@ -1,5 +1,6 @@
 const { processString, processObject, isValid } = require("../src/index.cjs")
 const tableJson = require("./examples/table.json")
+const dayjs = require("dayjs")
 
 describe("test the custom helpers we have applied", () => {
   it("should be able to use the object helper", async () => {
@@ -172,6 +173,24 @@ describe("test the date helpers", () => {
     const output = await processString("{{ date now 'DD' }}", {})
     expect(parseInt(output)).toBe(date.getDate())
   })
+
+  it("should test the timezone capabilities", async () => {
+    const date = new Date(1611577535000)
+    const output = await processString("{{ date time 'HH-mm-ss Z' 'America/New_York' }}", {
+      time: date.toISOString(),
+    })
+    expect(output).toBe("07-25-35 -04:00")
+  })
+
+  it("should guess the users timezone when not specified", async () => {
+    const date = new Date()
+    const output = await processString("{{ date time 'Z' }}", {
+      time: date.toISOString()
+    })
+    const timezone = dayjs.tz.guess()
+    const offset = new dayjs(date).tz(timezone).format("Z")
+    expect(output).toBe(offset)
+  })
 })
 
 describe("test the string helpers", () => {