.replace not working on \n in Javascript

Question

I have a Javascript string that ends in \n and I want to remove the last instance of \n through only regex. So I wrote this query /..$/ which targets it. However, when I run string1.replace(/..$/, "") the .replace still returns the original string and does not replace the last instance of \n with an empty string.

How can I use regex to remove those last two characters?

I've tried this

let string1 = '0,1,2,3,45\n10,11,12,13,14\n20,21,22,23,24\n30,31,32,33,34\n'

string1.replace(/..$/, "") 

=> '0,1,2,3,45\n10,11,12,13,14\n20,21,22,23,24\n30,31,32,33,34\n'

Do you *have to* use regex? Because you can just check the last character of the string and remove it if it's a new line, otherwise. — VLAZ, Dec 30 '17 at 19:54
yes, i know it's a cumbersome way of doing this, but it has to be regex. — Dog, Dec 30 '17 at 19:54
Are you sure you assign the result to a variable? Also, `.` does not match `\n`. You need to use `[\s\S]` to match any char including a newline. — Wiktor Stribiżew, Dec 30 '17 at 19:54
@Dog yes, but dot doesn't always match everything. Also, `\n` is not two characters but a single one. — VLAZ, Dec 30 '17 at 19:59
i get an invalid regex expression error with that combo and it doesn't work in rubular. the /..$/ regex expression is the only one that works in rubular. — Dog, Dec 30 '17 at 20:01
@Dog and @vlaz: it actually works on the Chrome console. Try it: `string1.replace(/.$/s, "")` — Jordão, Dec 30 '17 at 20:18
I suppose the default is a multi-line match, and the `s` treats the whole string as one line (`s` stands for single-line) — Jordão, Dec 30 '17 at 20:22
@Jordão it's not an official thing - doesn't work in Firefox and it's not even listed as an option on MDN. — VLAZ, Dec 30 '17 at 20:53
@vlaz you're right! Thanks for spotting that. It only works on Chrome then. Use at your own risk. How sad... — Jordão, Dec 30 '17 at 21:00

score 2 · Accepted Answer · answered Dec 30 '17 at 20:06

2

This worked in the console for me:

string1.replace(/\n$/,"");

answered Dec 30 '17 at 20:06

Collin G.

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That works. Rubular must recognize \n as characters so ..$ works there, but in console they aren't recognized and need to be specifically identified as \n. Thank you. – Dog Dec 30 '17 at 20:08

.replace not working on \n in Javascript

1 Answers1