JavaScript's getYear() method is a commonly used function for retrieving the year from a given date. However, many developers have noticed that this method often returns a three-digit number instead of the expected four-digit year. This has led to confusion and speculation about the reason behind this unusual behavior.
To understand why getYear() returns a three-digit number, we first need to look at how dates are represented in JavaScript. In JavaScript, dates are stored as the number of milliseconds since January 1, 1970, 00:00:00 UTC. This is known as the Unix Epoch time and is commonly used in many programming languages to represent dates.
When getYear() was first introduced in JavaScript, it was meant to return the year in two digits. For example, if the given date was January 1, 2000, the method would return 100. This was based on the assumption that the year 2000 would be represented as 00 in two digits. However, as we approached the year 2000, it became clear that this method would cause issues with the Y2K bug.
The Y2K bug was a problem in computer systems where dates were represented in two digits instead of four. This caused a fear that when the year 2000 arrived, these systems would interpret the date as 1900 instead of 2000, leading to potential errors and malfunctions. As a result, many developers started using the getFullYear() method instead, which returns a four-digit year and avoids the Y2K bug.
To address this issue, the creators of JavaScript decided to change the behavior of getYear() in the ECMAScript 3 standard. Instead of returning a two-digit year, it would return a four-digit year minus 1900. For example, if the given date was January 1, 2000, the method would now return 100 instead of 00. This change was made to ensure that the getYear() method would not cause any Y2K related issues.
However, this change also caused some confusion and inconsistencies. The getYear() method now returns a different result depending on which version of JavaScript is being used. In ECMAScript 3, it returns a two-digit year minus 1900, while in newer versions like ECMAScript 5, it returns a four-digit year minus 1900. This has led to the current situation where getYear() returns a three-digit number in most modern browsers.
Some developers have argued that this inconsistency makes the getYear() method unreliable and should be avoided altogether. Instead, they suggest using the getFullYear() method, which always returns a four-digit year. However, others argue that since the getYear() method still works as intended and is supported by most browsers, there is no need to abandon it completely.
In conclusion, the reason why getYear() returns a three-digit number is due to a combination of historical reasons and the need to prevent the Y2K bug. While this behavior may seem confusing and inconsistent, it is still a functional method for retrieving the year from a given date. As with any programming language, it is essential to understand the quirks and differences between versions to avoid any unexpected results.
