added getCustomIsoString

typescript/datetime/getCustomIsoString.ts

@@ -0,0 +1,28 @@
+/**
+ * Given a JS date returns a valid ISO date string with offset
+ *
+ * const myDate = new Date();
+ * console.log(getCustomIsoString(myDate));
+ * > 2021-07-07T13:35:18+02:00
+ *
+ */
+const getCustomIsoString = (date: Date) => {
+  /**
+   * If the month is smaller than 10, add a 0 in front of the string
+   */
+  const pad = (num: number): string => {
+    const norm = Math.floor(Math.abs(num));
+    return (norm < 10 ? "0" : "") + norm.toString();
+  };
+
+  const timeZoneOffset = -date.getTimezoneOffset();
+  const timeZoneDifference = timeZoneOffset >= 0 ? "+" : "-";
+
+  return `${date.getFullYear()}-${pad(date.getMonth() + 1)}-${pad(
+    date.getDate()
+  )}T${pad(date.getHours())}:${pad(date.getMinutes())}:${pad(
+    date.getSeconds()
+  )}${timeZoneDifference}${pad(timeZoneOffset / 60)}:${pad(
+    timeZoneOffset % 60
+  )}`;
+};