🔥 refactor(code): remove unused subtractYears function

Author: chriskyfung

src/code.js

@@ -103,19 +103,6 @@ function findMatchGroup(text, pattern) {
   return result === null ? null : result.groups?.exp || true;
 }
 
-/**
- * The function subtracts a specified number of years from a given date without mutating the original date.
- * @param {Date} date - The date parameter is a JavaScript Date object, representing a specific date and time.
- * @param {number} years - The "years" parameter is the number of years that you want to subtract from the given
- * date.
- * @returns {Date} the updated date after subtracting the specified number of years.
- */
-function subtractYears(date, years) {
-  const newDate = new Date(date);
-  newDate.setFullYear(newDate.getFullYear() - years);
-  return newDate;
-}
-
 /**
  * The main function searches for messages that match a given query string, extracts text using a
  * pattern, and checks if the extracted text is overdue based on a date formatter function.
@@ -182,7 +169,6 @@ function main(
   });
 }
 
-globalThis.subtractYears = subtractYears;
 globalThis.checkOverdue = checkOverdue;
 globalThis.findMatchGroup = findMatchGroup;
 globalThis.getLastMessageDate = getLastMessageDate;
@@ -191,7 +177,6 @@ globalThis.main = main;
 
 if (typeof module !== 'undefined' && module.exports) {
   module.exports = {
-    subtractYears,
     checkOverdue,
     findMessages,
     findMatchGroup,

test/code.test.js

@@ -1,20 +1,6 @@
-const { subtractYears, checkOverdue, findMessages } = require('../src/code.js');
+const { checkOverdue, findMessages } = require('../src/code.js');
 
 describe('Core Functions', () => {
-  describe('subtractYears', () => {
-    it('should subtract 1 year from the given date', () => {
-      const date = new Date('2025-01-01');
-      const newDate = subtractYears(date, 1);
-      expect(newDate.getFullYear()).toBe(2024);
-    });
-
-    it('should return a new date object and not mutate the original', () => {
-      const originalDate = new Date('2025-01-01');
-      const originalTime = originalDate.getTime();
-      subtractYears(originalDate, 1);
-      expect(originalDate.getTime()).toBe(originalTime);
-    });
-  });
 
   describe('checkOverdue', () => {
     const mockNow = new Date('2025-08-19T00:00:00.000Z').getTime();