How to compare dates using JavaScript

In JavaScript, Date is a built-in object that represents a specific point in time. It provides methods and properties to work with dates and times.

This Answer provides a comparison between two dates in JavaScript, along with practical examples to aid in understanding their implementation.

One approach to compare two dates in JavaScript involves converting them into numeric values that represent their respective time. Using the getTime() function, we can transform the Date object into a numeric value. Once both dates are converted into numeric values, direct comparison becomes possible.

Note: The getTime() method enables us to perform various forms of date comparisons using comparison operators such as >, <, <=, >=, ==, ===, !=, and !==.

Comparing dates with equality operators

To perform equality comparisons in JavaScript, utilize the Date object along with the getTime() method, which returns the number of milliseconds. For more specific details such as the day, month, and more, employ additional date methods like getDate(), getHours(), getDay(), getMonth(), and getYear().

Code example 1

Explanation

Here’s the explanation of the code above.

• Lines 1–2: We create two Date objects, i.e, currentDate, and anotherDate, using the new Date() constructor, which initializes them with the current date and time.

• Lines 4–5: We check if the values of date1 and date2 are equal using the === operator. We also use getTime(), which returns the numeric value representing the number of milliseconds. If the numeric values are equal, the code executes the block inside the if statement, which logs the message “Both dates are equal” to the console.

• Lines 6–8: If the numeric values are not equal, the code executes the block inside the else statement, which logs the message “Dates are not equal” to the console.

We can make a comparison by providing various dates as inputs to the date object.

Code example 2

Explanation

Here’s the explanation of the code above.

• Lines 1–2: We declare date1 and date2 using the new Date() constructor, which initializes them with the current date and time. We also take the arguments of different dates, respectively.

• Lines 4–5: If the numeric values are not equal, the code executes the block inside the if statement, which logs the message “Dates are not equal” to the console.

• Lines 6–8: If the numeric values are equal, the code executes the block inside the else statement, which logs the message “Both dates are equal” to the console.

Comparing dates with relational operators

To perform a specific date comparison, we can utilize the getFullYear() method of the date object in the following manner when comparing specific values like the year.

Code example 3

Explanation

Here’s an explanation of the above code .

• Lines 1–2: We declare two Date objects: date1 with the date “2023-05-26”, and date2 with the date “2021-07-28”.

• Lines 4–5: We use the getFullYear() method to extract the full-year value from date1 and date2, and store them in year1 and year2, respectively.

• Lines 7–13: We use an if statement to compare year1 and year2:

  • If year1 is less than year2, the code block inside the if statement is executed, and the message “Year1 is earlier than Year2” is logged to the console.

  • If year1 is greater than year2, the code block inside the else if statement is executed, and the message “Year1 is later than Year2” is logged to the console.

  • If neither of the conditions above is true, the code block inside the else statement is executed, and the message “Both years are equal” is logged.