go integration and wikipedia

frontend/node_modules/date-fns/isFirstDayOfMonth.js

@@ -0,0 +1,26 @@
+"use strict";
+exports.isFirstDayOfMonth = isFirstDayOfMonth;
+var _index = require("./toDate.js");
+
+/**
+ * @name isFirstDayOfMonth
+ * @category Month Helpers
+ * @summary Is the given date the first day of a month?
+ *
+ * @description
+ * Is the given date the first day of a month?
+ *
+ * @typeParam DateType - The `Date` type, the function operates on. Gets inferred from passed arguments. Allows to use extensions like [`UTCDate`](https://github.com/date-fns/utc).
+ *
+ * @param date - The date to check
+
+ * @returns The date is the first day of a month
+ *
+ * @example
+ * // Is 1 September 2014 the first day of a month?
+ * const result = isFirstDayOfMonth(new Date(2014, 8, 1))
+ * //=> true
+ */
+function isFirstDayOfMonth(date) {
+  return (0, _index.toDate)(date).getDate() === 1;
+}