From 30b7af1dbec405b02df794a799a24c6f35dfbdc5 Mon Sep 17 00:00:00 2001
From: Jakob Stendahl <jakob.stendahl@outlook.com>
Date: Mon, 2 May 2022 23:06:37 +0200
Subject: Convert all date strings to ISO861, do some minor design fixes

---
 src/lib/DateUtils.js | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 src/lib/DateUtils.js

(limited to 'src/lib/DateUtils.js')

diff --git a/src/lib/DateUtils.js b/src/lib/DateUtils.js
new file mode 100644
index 0000000..cf3e4da
--- /dev/null
+++ b/src/lib/DateUtils.js
@@ -0,0 +1,66 @@
+/* LUT for date-number from month name. */
+const MonthNumber = {
+    "January": 1, "Feb": 2, "March": 3, "April": 4, "May": 5, "June": 6, "July": 7, "August": 8, "September": 9, "October": 10, "November": 11, "December": 12
+}
+
+/**
+ * Padds a string (or number) with leading zeroes.
+ * @param  {string}     number The string to be padded.
+ * @param  {number} [2] n      The minimum width of the returned string.
+ * @return {string}            Zero-padded string.
+ */
+function zpad(number, n=2) {
+    let ret = number.toString();
+    while (n - ret.length > 0) {
+        ret = "0" + ret;
+    }
+    return ret
+}
+
+/**
+ * Attempts to recognize date-string pattern and convert into ISO861.
+ * @param  {string} dateStr A String representing the time, UTC will be assumed
+ *                          unless it is valid ISO861 with a different timezone.
+ * @return {string}         dateStr as ISO861. If no pattern was found (or it
+ *                          already is valid ISO861. The string will be returned
+ *                          with no changes.
+ */
+function toISO861UTC(dateStr) {
+    // yyyy-mm-ddThh:mm:ssZ
+    if (/^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}Z$/.test(dateStr)) {
+        //console.log(`yyyy-mm-ddThh:mm:ssZ <- ${dateStr}`);
+        return dateStr;
+    }
+
+    // yyyy MMMM dd
+    if (/^\d{4}\s[a-z,A-Z]+\s\d{2}$/.test(dateStr)) {
+        //console.log(`yyyy MMM dd <- ${dateStr}`);
+        let parts = dateStr.split(" ");
+        dateStr = (`${parts[0]}-${zpad(MonthNumber[parts[1]])}-${parts[2]}T00:00:00Z`);
+        return dateStr;
+    }
+
+    // yyyy mm dd hh:mm:ss
+    if (/^\d{4}-\d{2}-\d{2}\s\d{2}:\d{2}:\d{2}/.test(dateStr)) {
+        return dateStr.replace(" ", "T") + "Z";
+    }
+
+    // yyyy mm dd hh:mm:ss.msm
+    if (/^\d{4}-\d{2}-\d{2}\s\d{2}:\d{2}:\d{2}.\d{4}/.test(dateStr)) {
+        return dateStr.replace(" ", "T").split(".")[0] + "Z";
+    }
+
+    console.warn(dateStr);
+    return dateStr;
+}
+
+/**
+ * Returns a date object from a date-string.
+ * @param {string} dateStr A String representing the time, UTC will be assumed
+ *                         unless it is valid ISO861 with a different timezone.
+ * @return {Date}          The date object representing the date-string.
+ */
+export function parseDateAsUTC(dateStr) {
+    dateStr = toISO861UTC(dateStr);
+    return new Date(dateStr);
+}
-- 
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