Create 1154-day-of-the-year.js

Author: everthis

1154-day-of-the-year.js

@@ -0,0 +1,11 @@
+/**
+ * @param {string} date
+ * @return {number}
+ */
+
+const dayOfYear = function(date) {
+  const [year, month, day] = date.split('-').map(s => +s),
+    months = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31],
+    isLeapYear = !(year % 4) && month > 2 && (!!(year % 100) || !(year % 400))
+  return months.splice(0, month - 1).reduce((a, b) => a + b, day + +isLeapYear)
+}