How to match range of dates using regular expressions

Question

I have, for example, this date range sentence to test: from 10-08-2024 to 12-08-2024, I need to extract the dates.

I have used Regex101 site to design the regular expressing, getting this one:

^(from)\s((?:0[1-9]|[12][0-9]|3[01])-(?:0[1-9]|1[1,2])-(?:19|20)\d{2})\s(to)\s((?:0[1-9]|[12][0-9]|3[01])-(?:0[1-9]|1[1,2])-(?:19|20)\d{2})$

It works, however, all are returned as groups instead of matches.

as you see, start and end dates are returned as groups. The only match is the whole sentence.

How can I get the dates to be returned as match 2 and match 3 instead of group 2 and group 4, respectively?

Thanks Jaime

Answer 1

You can use positive lookbehind to check (from|to) followed by the date regex that you have provided.

(?<=(?:from|to)\s*)(?:(?:0[1-9]|[12][0-9]|3[01])-(?:0[1-9]|1[1,2])-(?:19|20)\d{2})

Demo

Here you get your dates as match 1 and match 2.

Sample source:

const regex = /(?<=(?:from|to)\s*)(?:(?:0[1-9]|[12][0-9]|3[01])-(?:0[1-9]|1[1,2])-(?:19|20)\d{2})/gm;

const str = `from 10-08-2024 to 12-08-2024`;
let m;

while ((m = regex.exec(str)) !== null) {
    m.forEach((match) => {
        console.log(match);
    });
}