Javascript regex between string delimiters

Question

I have the following string:

%||1234567890||Joe||% some text winter is coming %||1234567890||Robert||%

PROBLEM: I am trying to match all occurrences between %||....||% and process those substring matches

MY REGEX: /%([\s\S]*?)(?=%)/g

MY CODE

var a = "%||1234567890||Joe||% some text winter is coming %||1234567890||Robert||%";

var pattern = /%([\s\S]*?)(?=%)/g;

a.replace( pattern, function replacer(match){
    return match.doSomething();
} );

Now the patterns seems to be selecting the everything between the first and last occurrence of %|| .... %||

MY FIDDLE

WHAT I NEED:

I want to iterate over the matches

%||1234567890||Joe||%

AND

%||1234567890||Robert||%

and do something

Try replacing the pattern with /%\|\|([\s\S]*?)(?=\|\|%)/g or even /%\|\|([\s\S]*?)\|\|%/g - regex101.com/r/ugkkNa/1. Then use the a = a.replace(/pattern/g, function ($0, $1) {return ...;}) — Wiktor Stribiżew
– Wiktor Stribiżew, Commented Mar 31, 2017 at 9:05

Wiktor Stribiżew · Accepted Answer · 2017-03-31 09:16:33Z

1

You need to use a callback inside a String#replace and modify the pattern to only match what is inside %|| and ||% like this:

var a = "%||1234567890||Joe||% some text winter is coming %||1234567890||Robert||%";
var pattern = /%\|\|([\s\S]*?)\|\|%/g;
a = a.replace( pattern, function (match, group1){
    var chunks = group1.split('||');
    return "{1}" + chunks.join("-") + "{/1}";
} );
console.log(a);

The /%\|\|([\s\S]*?)\|\|%/g pattern will match:

%\|\| - a %|| substring
([\s\S]*?) - Capturing group 1 matching any 0+ chars as few as possible up to the first...
\|\|% - a ||% substring
/g - multiple times.

edited Mar 31, 2017 at 9:16

answered Mar 31, 2017 at 9:11

Wiktor Stribiżew

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1 Comment

Neil Over a year ago

Simply brilliant! Thank you Wiktor :)

Kulvar · Accepted Answer · 2017-03-31 09:13:37Z

0

Because he tries to take as much as possible, and [\s\S] basically means "anything". So he takes anything.

RegExp parts without escaping, exploded for readability
start tag : %||
first info: ([^|]*) // will stop at the first |
separator : ||
last info : ([^|]*) // will stop at the first |
end tag   : ||%

Escaped RegExp:
/%\|\|([^\|]*)\|\|([^\|]*)\|\|%/g

answered Mar 31, 2017 at 9:13

Kulvar

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3 Comments

Wiktor Stribiżew Over a year ago

This regex won't match values like %||123456|7890||Joe||%

Kulvar Over a year ago

You're not supposed to use the delimiting character in the values. But from the exemples given, it won't happen.

Wiktor Stribiżew Over a year ago

From the examples given, the delimiter is a 2-char string.

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