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diff --git a/date-fns/src/formatISODuration/index.js b/date-fns/src/formatISODuration/index.js
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+import requiredArgs from '../_lib/requiredArgs/index'
+
+/**
+ * @name formatISODuration
+ * @category Common Helpers
+ * @summary Format a duration object according as ISO 8601 duration string
+ *
+ * @description
+ * Format a duration object according to the ISO 8601 duration standard (https://www.digi.com/resources/documentation/digidocs/90001437-13/reference/r_iso_8601_duration_format.htm)
+ *
+ * @param {Duration} duration - the duration to format
+ *
+ * @returns {String} The ISO 8601 duration string
+ * @throws {TypeError} Requires 1 argument
+ * @throws {Error} Argument must be an object
+ *
+ * @example
+ * // Format the given duration as ISO 8601 string
+ * formatISODuration({
+ *   years: 39,
+ *   months: 2,
+ *   days: 20,
+ *   hours: 7,
+ *   minutes: 5,
+ *   seconds: 0
+ * })
+ * //=> 'P39Y2M20DT0H0M0S'
+ */
+
+export default function formatISODuration(duration) {
+  requiredArgs(1, arguments)
+
+  if (typeof duration !== 'object')
+    throw new Error('Duration must be an object')
+
+  const {
+    years = 0,
+    months = 0,
+    days = 0,
+    hours = 0,
+    minutes = 0,
+    seconds = 0
+  } = duration
+
+  return `P${years}Y${months}M${days}DT${hours}H${minutes}M${seconds}S`
+}