Why does this regex execution not return the match

Question

My regex is:

let a = new RegExp("(?:https?:)?\/\/(?:www\.)?(?:facebook|fb)\.com\/(?<profile>(?![A-z]+\.php)(?!marketplace|gaming|watch|me|messages|help|search|groups)[\w.\-]+)\/?", "g")

It's basically a modification of the one seen here for facebook to extract the username from a facebook url.

My test string is https://facebook.com/peterparker and my code is:

a.exec("https://facebook.com/peterparker")

When I try this in RegExr, it works fine. It shows the correct group captured (peterparker).

Yet, when I try the same code in Google Chrome's console, the code returns null:

Why doesn't it show up in the chrome console?

The "Named capture groups" feature may not be supported on all browsers. Did you try on other browsers? — Samil Kahraman, Feb 26 '22 at 09:10
can you try to save c.exec in a variable something like var test = exec("https://facebook.com/peterparker") and then do test or console.log(test) ? — Marcogomesr, Feb 26 '22 at 09:13
@SamilKahraman RegExr uses the same code so it definitely was not a browser issue. — callmekatootie, Feb 26 '22 at 09:59

score 1 · Accepted Answer · answered Feb 26 '22 at 09:11

Since you're creating your regex from a string, you have to escape your backslashes.

let a = new RegExp("(?:https?:)?\/\/(?:www\.)?(?:facebook|fb)\\.com\/(?<profile>(?![A-z]+\\.php)(?!marketplace|gaming|watch|me|messages|help|search|groups)[\\w.\\-]+)\\/?", "g")
console.log(a.exec("https://facebook.com/peterparker"))

Creating it inline does not have this problem.

let a = /(?:https?:)?\/\/(?:www\.)?(?:facebook|fb)\.com\/(?<profile>(?![A-z]+\.php)(?!marketplace|gaming|watch|me|messages|help|search|groups)[\w.\-]+)\/?/g
console.log(a.exec("https://facebook.com/peterparker"))

This was it. Thank you. Was driving me crazy – callmekatootie Feb 26 '22 at 09:46 — callmekatootie, Feb 26 '22 at 09:46

Why does this regex execution not return the match

1 Answers1