Merge pull request #8358 from surveyjs/features/8357-datediff

Add dateDiff function into function factory fix #8357

src/functionsfactory.ts

@@ -235,22 +235,30 @@ function getDate(params: any[]): any {
 }
 FunctionFactory.Instance.register("getDate", getDate);
 
-function age(params: any[]): any {
-  if (!params && params.length < 1) return null;
-  if (!params[0]) return null;
-  const birthDate = new Date(params[0]);
-  const today = new Date();
-  let age = today.getFullYear() - birthDate.getFullYear();
-  if(age > 0) {
-    const m = today.getMonth() - birthDate.getMonth();
-    if (m < 0 || (m === 0 && today.getDate() < birthDate.getDate())) {
-      age -= 1;
-    }
+function dateDiffMonths(date1Param: any, date2Param: any, type: string): number {
+  if(type === "days") return diffDays([date1Param, date2Param]);
+  const date1 = !!date1Param ? new Date(date1Param) : new Date();
+  const date2 = !!date2Param ? new Date(date2Param) : new Date();
+  const age = date2.getFullYear() - date1.getFullYear();
+  type = type || "years";
+  let ageInMonths = age * 12 + date2.getMonth() - date1.getMonth();
+  if (date2.getDate() < date1.getDate()) {
+    ageInMonths -= 1;
   }
-  return age;
+  return type === "months" ? ageInMonths : ~~(ageInMonths / 12);
+}
+function age(params: any[]): number {
+  if(!Array.isArray(params) || params.length < 1 || !params[0]) return null;
+  return dateDiffMonths(params[0], undefined, (params.length > 1 ? params[1] : "") || "years");
 }
 FunctionFactory.Instance.register("age", age);
 
+function dateDiff(params: any[]): any {
+  if(!Array.isArray(params) || params.length < 2 || !params[0] || !params[1]) return null;
+  return dateDiffMonths(params[0], params[1], (params.length > 2 ? params[2] : "") || "days");
+}
+FunctionFactory.Instance.register("dateDiff", dateDiff);
+
 function isContainerReadyCore(container: any): boolean {
   if (!container) return false;
   var questions = container.questions;

tests/expressions/expressionParserTest.ts

@@ -339,7 +339,37 @@ QUnit.test("Run age function, Bug#2562", function(assert) {
   values.birthday = date;
   assert.equal(runner.run(values), 79, "one day till 80");
 });
-
+QUnit.test("Run dateDiff by years function", function(assert) {
+  const runner = new ExpressionRunner("dateDiff({birthday}, {currentDate}, 'years')");
+  const values = { birthday: new Date(1974, 10, 10), currentDate: new Date(2014, 11, 11) };
+  assert.equal(runner.run(values), 40, "Use the second parameter");
+});
+QUnit.test("Run age by months function", function(assert) {
+  const runner = new ExpressionRunner("age({birthday}, 'months')");
+  var date = new Date(Date.now());
+  date.setFullYear(date.getFullYear() - 10);
+  const values = { birthday: date };
+  assert.equal(runner.run(values), 10 * 12, "10 years old, bithday is today");
+  date = new Date(date.getTime() + 60 * 60 * 24 * 1000);
+  values.birthday = date;
+  assert.equal(runner.run(values), 9 * 12 + 11, "9 years + 11 months");
+});
+QUnit.test("Run dateDiff by months", function(assert) {
+  const runner = new ExpressionRunner("dateDiff({birthday}, {currentDate}, 'months')");
+  const values = { birthday: new Date(2012, 10, 10), currentDate: new Date(2014, 11, 11) };
+  assert.equal(runner.run(values), 2 * 12 + 1, "Use the second parameter, #1");
+  values.currentDate = new Date(2014, 11, 9);
+  assert.equal(runner.run(values), 2 * 12, "Use the second parameter, #2");
+});
+QUnit.test("Run dateDiff by days", function(assert) {
+  var runner = new ExpressionRunner("dateDiff({d1}, {d2})");
+  var d1 = new Date("2021-01-01");
+  var d2 = new Date("2021-02-02");
+  const values = { d1: d1, d2: d2 };
+  assert.equal(runner.run(values), 32, "32 days");
+  (<any>values).d1 = undefined;
+  assert.equal(runner.run(values), null, "a value is undefined");
+});
 QUnit.test("Run getYear() function", function(assert) {
   var runner = new ExpressionRunner("getYear({birthday})");
   var values = { birthday: new Date(1974, 1, 1) };