Added basic date maths (release 0.1.0.021)

ryjsxt.js

@@ -1,6 +1,6 @@
 /**
  * Ray's JavaScript Extension
- * @version v0.1.0.018 (2023/12/09 0356)
+ * @version v0.1.0.021 (2023/12/11 0056)
  */
 
 
@@ -166,6 +166,42 @@ Boolean.ifTrue = function(value, trueValue, falseValue) {
 
 
 
+Date.addDays = function (date, days) {
+  let result = new Date(date);
+
+  result.addDays(days);
+
+  return result;
+};
+
+Date.addMonths = function (date, months) {
+  let result = new Date(date);
+
+  result.addMonths(months);
+
+  return result;
+};
+
+Date.addYears = function (date, years) {
+  let result = new Date(date);
+
+  result.addYears(years);
+
+  return result;
+};
+
+Date.prototype.addDays = function (days) {
+  this.setDate(this.getDate() + parseInt(days));
+}
+
+Date.prototype.addMonths = function (months) {
+  this.setMonth(this.getMonth() + parseInt(months));
+}
+
+Date.prototype.addYears = function (years) {
+  this.setFullYear(this.getFullYear() + parseInt(years));
+}
+
 Date.prototype.toCString = function(pattern) {
   let result = pattern;