How do i combine 3 regex patterns in JS replace() method on a string?

Question

-ANSWER to this example is 'var pattern = /(\\n)|(\\r)|(\\t)/g;'

-ANSWER to question is, you can put each pattern in parentheses, separate with a pipe symbol and assign the global identifier at the end of the regex.

TA DA! :)

TRY THIS LINK FOR A HELPFUL REGEX TOOL: https://regex101.com/#javascript

I thought that simple questions like how do you combine regexes would get a simple answer - i don't believe there's a straight answer on the tutorial. But i recommend reading the manual.

I've read a few suggested answers most seem to focus on the pipe OR operator, but i want to combine regexes. Shamefully newbie at regexes. Anyway, I want to remove special characters from tab, space and return. Here's what I have:

            var pattern1 = /(\\n)/g;
            var pattern2 = /(\\t)/g;
            var pattern3 = /(\\r)/g;

            $heading = $heading.replace(pattern1, "");
            $heading = $heading.replace(pattern2, "");
            $heading = $heading.replace(pattern3, "");

This works, however it is repeating and I can't find any info on how to create one regex pattern that will look for all and remove them.

@sjingo Please clarify whether you want to replace *literal* `\n`s, etc. or *actual* newlines, etc. — Biffen, Mar 30 '16 at 10:56
OP, please clarify your question. "I want to remove all special characters" that's not what your current regex does. Please [edit] and make it clear what it is that's the problem. — Madara's Ghost, Mar 30 '16 at 11:00
hi, thank you for all your comments. i enjoy learning for myself but am on a deadline for something hence the post. — sjingo, Mar 30 '16 at 11:22
not sure why this is marked down, but please rest assured i have been googling for hours and read through lots of StackOverflow answers first. — sjingo, Mar 30 '16 at 11:23
@Biffen - hi Biffen. so, i want to simply remove any tabs, spaces or returns from my string, which i will pass out as json format from an ajax call to a php file / db and then that will help recreate elements on another page. — sjingo, Mar 30 '16 at 11:32
@Wiktor and MaraUchiha - i admit it. i need to read up. as you can appreciate it's not a quick process. I really appreciate all the responses . I still don't have a solution but my original code works — sjingo, Mar 30 '16 at 11:34
@sjingo Then you should try user6134246's answer - that is what you need. — Wiktor Stribiżew, Mar 30 '16 at 11:38
@Wiktor - i will try that thanks. all the links are useful. shame i didn't quite get to combine my statements. your suggestion did not work. — sjingo, Mar 30 '16 at 11:39
If your code works, always consider posting the question at [codereview.se] — Wiktor Stribiżew, Mar 30 '16 at 11:40
i take it none of you actually know the answer then - so really this has been a complete waste of time. — sjingo, Mar 30 '16 at 11:51
You've gotten 2 correct answers to your very vague question. You've completely ignored anything we said about editing and clarifying what you want, and you're complaining that this was a waste of *your* time? I'm closing this question, and I apologize @WiktorStribiżew for disputing his decision earlier. — Madara's Ghost, Mar 30 '16 at 11:56
lol. don't reply if it wastes your time. i thought this place was meant to have helpful people posting helpful answers. i couldn't get your solution working sorry. — sjingo, Mar 30 '16 at 13:41

user6134246 · Answer 1 · 2016-03-30T11:17:27.883

1

You can combine them using logical ORs.

var pattern = /(\\t|\\n|\\r)/g;
$heading = $heading.replace(pattern1, "");

Using Wiktor Stribiżew approach, but for escaped special chars you could use/\\[trn]/g to match a backslash followed by any of the three characters.

edited Mar 30 '16 at 11:17

answered Mar 30 '16 at 10:50

user6134246

11
2

1

\\ counts as two characters. – user6134246 Mar 30 '16 at 10:53
ok one can do it for escaped special chars with classes too (plus he asked for a solution not using OR). – user6134246 Mar 30 '16 at 11:19
Correct answer here. – sjingo Mar 30 '16 at 13:58
@sjingo if this is the most helpful answer, click the hollow checkmark underneath the voting arrows. See: http://stackoverflow.com/help/accepted-answer – skrrgwasme Mar 30 '16 at 15:58

score 0 · Answer 2 · answered Mar 30 '16 at 11:09

Use the bar | to separate patterns with a logical OR. For your example, I would use the pattern

var pattern = /\r|\t|\n/g;

You can also use pattern.source to get the actual regex expression. That way, you can combine them at a later stage. Like this:

var pattern1 = /\r/;
var pattern2 = /\t/;
var combined = new RegExp(pattern1.source + '|' + pattern2.source);
combined.source
=> '\\r|\\t'

That pattern will match any carriage return, tab or newline in your test string. See here for a working example.

Also, check out https://regex101.com/#javascript. It's a great tool for figuring out regexes.

hey Larslonne. thanks your answer was the most helpful. – sjingo Mar 30 '16 at 13:46 — sjingo, Mar 30 '16 at 13:46

How do i combine 3 regex patterns in JS replace() method on a string?

2 Answers2