Consider precision in successor/predecessor of date

Author: cmoesel

examples/browser/cql4browsers.js

@@ -1488,8 +1488,11 @@ class Date extends AbstractDate {
     copy() {
         return new Date(this.year, this.month, this.day);
     }
-    successor() {
-        if (this.day != null) {
+    successor(precision) {
+        if (precision) {
+            return this.add(1, precision);
+        }
+        else if (this.day != null) {
             return this.add(1, Date.Unit.DAY);
         }
         else if (this.month != null) {
@@ -1499,8 +1502,11 @@ class Date extends AbstractDate {
             return this.add(1, Date.Unit.YEAR);
         }
     }
-    predecessor() {
-        if (this.day != null) {
+    predecessor(precision) {
+        if (precision) {
+            return this.add(-1, precision);
+        }
+        else if (this.day != null) {
             return this.add(-1, Date.Unit.DAY);
         }
         else if (this.month != null) {

src/datatypes/datetime.ts

@@ -1090,8 +1090,10 @@ export class Date extends AbstractDate {
     return new Date(this.year, this.month, this.day);
   }
 
-  successor() {
-    if (this.day != null) {
+  successor(precision?: string) {
+    if (precision) {
+      return this.add(1, precision);
+    } else if (this.day != null) {
       return this.add(1, Date.Unit.DAY);
     } else if (this.month != null) {
       return this.add(1, Date.Unit.MONTH);
@@ -1100,8 +1102,10 @@ export class Date extends AbstractDate {
     }
   }
 
-  predecessor() {
-    if (this.day != null) {
+  predecessor(precision?: string) {
+    if (precision) {
+      return this.add(-1, precision);
+    } else if (this.day != null) {
       return this.add(-1, Date.Unit.DAY);
     } else if (this.month != null) {
       return this.add(-1, Date.Unit.MONTH);

test/datatypes/date-test.ts

@@ -196,6 +196,36 @@ describe('Date.add', () => {
   });
 });
 
+describe('Date.successor', () => {
+  it('should use the specified precision', () => {
+    const date = Date.parse('2000-06-15');
+    date.successor(Date.Unit.YEAR).should.eql(Date.parse('2001-06-15'));
+    date.successor(Date.Unit.MONTH).should.eql(Date.parse('2000-07-15'));
+    date.successor(Date.Unit.DAY).should.eql(Date.parse('2000-06-16'));
+  });
+
+  it("should use the date's finest precision when precision is not specified", () => {
+    Date.parse('2000-06-15').successor().should.eql(Date.parse('2000-06-16'));
+    Date.parse('2000-06').successor().should.eql(Date.parse('2000-07'));
+    Date.parse('2000').successor().should.eql(Date.parse('2001'));
+  });
+});
+
+describe('Date.predecessor', () => {
+  it('should use the specified precision', () => {
+    const date = Date.parse('2000-06-15');
+    date.predecessor(Date.Unit.YEAR).should.eql(Date.parse('1999-06-15'));
+    date.predecessor(Date.Unit.MONTH).should.eql(Date.parse('2000-05-15'));
+    date.predecessor(Date.Unit.DAY).should.eql(Date.parse('2000-06-14'));
+  });
+
+  it("should use the date's finest precision when precision is not specified", () => {
+    Date.parse('2000-06-15').predecessor().should.eql(Date.parse('2000-06-14'));
+    Date.parse('2000-06').predecessor().should.eql(Date.parse('2000-05'));
+    Date.parse('2000').predecessor().should.eql(Date.parse('1999'));
+  });
+});
+
 describe('Date.differenceBetween', () => {
   it('should return null if passed a non-Date object', () => {
     const a = Date.parse('2018-01-23');

test/datatypes/interval-test.ts

@@ -384,6 +384,17 @@ describe('Interval', () => {
   });
 });
 
+describe('DateInterval', () => {
+  it('should use the specified precision for meets comparisons', () => {
+    const january = new Interval(Date.parse('2020-01-01'), Date.parse('2020-01-15'));
+    const february = new Interval(Date.parse('2020-02-15'), Date.parse('2020-02-28'));
+
+    january.meets(february, Date.Unit.MONTH).should.be.true();
+    january.meetsBefore(february, Date.Unit.MONTH).should.be.true();
+    february.meetsAfter(january, Date.Unit.MONTH).should.be.true();
+  });
+});
+
 describe('DateTimeInterval', () => {
   describe('contains', () => {
     let d: any;