Add previous business day

README.md

@@ -37,6 +37,10 @@ Returns if the supplied date is a business day.
 
 Returns the next business day after `day`.
 
+## previousBusinessDay(country, date, options)
+
+Returns the previous business day before `day`.
+
 # License
 
 Check [here](LICENSE).

lib/index.js

@@ -73,6 +73,23 @@ exports.nextBusinessDay = function(country, anchorDate, options) {
 	}
 };
 
+exports.previousBusinessDay = function(country, anchorDate, options) {
+	const day = moment(sanitizeDateInput(anchorDate)).subtract(1, 'd');
+
+	return iterate(day);
+
+	function iterate(day) {
+		return exports.isBusinessDay(country, day, options)
+		.then(function(isBusinessDay) {
+			if (isBusinessDay) {
+				return day.toDate();
+			}
+
+			return iterate(day.subtract(1, 'd'));
+		});
+	}
+};
+
 function getDateFromInformation(info, date) {
 	var key = date.format('YYYY-MM-DD');
 

test/query.js

@@ -30,5 +30,12 @@ describe('Query', function() {
 			return expect(bm.nextBusinessDay('brazil', new Date(2016, 1, 5, 10))).to.eventually.eql(new Date(2016, 1, 10, 10));
 		});
 	});
+
+	describe('previousBusinessDay', function() {
+		it('should return the correct day', function() {
+			return expect(bm.previousBusinessDay('brazil', new Date(2021, 5, 4, 10)))
+				.to.eventually.eql(new Date(2021, 5, 2, 10));
+		});
+	});
 });