Is there a glitch in JavaScript when comparing dates?

What's wrong with this code?

function test() { 
    var start = new Date(2012, 3, 31, 19, 0, 0); // Start: 3/31/2012 7:00 PM
    var end = new Date(2012, 4, 1, 1, 0, 0);     // End: 4/01/2012 1:00 AM

    if (end < start)
        console.log("oops!");
    else
        console.log("works!");
}

Result:

oops!

Answer №1

Remember, in JavaScript, months are counted starting from 0.

let start = new Date(2012, 2, 31, 19, 0, 0); // March 31, 2012 at 7:00 PM
let end = new Date(2012, 3, 1, 1, 0, 0);     // April 1, 2012 at 1:00 AM

In this scenario, both the start and end dates will be May 1, 2012. Simply print out the values to confirm.

Answer №2

Here are the resolved dates:

Tue May 01 2012 19:00:00 GMT-0700 (PDT)
Tue May 01 2012 01:00:00 GMT-0700 (PDT)

As stated on Mozilla Developer Network:

month
This value represents the month, starting with 0 for January and ending with 11 for December.

Answer №3

Are you looking to determine which date comes first?

When comparing dates, remember that you are actually comparing objects. You can use the following code:

if(end.valueOf() < start.valueOf()) { //do stuff }

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