I'm trying, in javascript, to get a regexp to match areas contained by curly braces (and including) in a string where there are one or more line breaks, and possible tag nesting. So it would match {the quick brown fox ... lazy dog} inside the string:

did you know {the quick brown fox
jumps

over the lazy dog} is a pangram?

but not the curly braced area inside the following string, as it doesn't contain a line break

did you know {the quick brown fox jumps over the lazy dog} is a pangram?

I'm ing unstuck when there is nesting, because I want only brown \n fox to match in the following example, since it is the immediate brace containing the line break.

did you know {the quick {brown
fox} jumps over the lazy dog} is
a pangram?

the obvious /\{([^{]+)\}/g will match anything inside a curly set, but that can mean it can erroneously match on {the quick {brown \n fox} and {brown \n fox} jumps over the lazy dog}. I'm starting to think that substring matching might be the way, something like the way a css template system like mustache js does it.

I'm trying, in javascript, to get a regexp to match areas contained by curly braces (and including) in a string where there are one or more line breaks, and possible tag nesting. So it would match {the quick brown fox ... lazy dog} inside the string:

did you know {the quick brown fox
jumps

over the lazy dog} is a pangram?

but not the curly braced area inside the following string, as it doesn't contain a line break

did you know {the quick brown fox jumps over the lazy dog} is a pangram?

I'm ing unstuck when there is nesting, because I want only brown \n fox to match in the following example, since it is the immediate brace containing the line break.

did you know {the quick {brown
fox} jumps over the lazy dog} is
a pangram?

the obvious /\{([^{]+)\}/g will match anything inside a curly set, but that can mean it can erroneously match on {the quick {brown \n fox} and {brown \n fox} jumps over the lazy dog}. I'm starting to think that substring matching might be the way, something like the way a css template system like mustache js does it.

• javascript
• regex

6 Answers 6

To ensure there are at least one newline char in the string, use the regex like below:

/\{(?=.*\n)[^}]+\}/

console:

> "aaa{ccc}bbb".match(/\{(?=.*\n)[^}]+\}/)
  null
> "aaa{ccc\ndddd}bbb".match(/\{(?=.*\n)[^}]+\}/)
  ["{ccc
  dddd}"]

This pattern will work /\{(?=.*\s)[^{}]+\}/

From console

a = "aa{aaaa
bb}b"
b = "aaaa{cccc}bbb"
c = "aaaaaaa{sssss{ddd
dd}bbb}sss"

a.match(/\{(?=.*\s)[^{}]+\}/)
["{aaaa
bb}"]
b.match(/\{(?=.*\s)[^{}]+\}/)
null
c.match(/\{(?=.*\s)[^{}]+\}/)
["{ddd
dd}"]

try this one:

   \{([^{\n]+)\}

I tested it here: http://regex101./r/vJ6gU1

I think this is what you're after:

/\{[^{}\n]*\n[^{}]*\}/

[^{}\n]*\n consumes everything up to the next linefeed, but it fails if it sees a brace first.

Then [^{}]* consumes the rest because it doesn't matter if there are any more linefeeds.

I'm assuming your line separators consist of linefeed alone (\n) or carriage return plus linefeed (\r\n). There are some other possibilities, but they're very rare.

This one works for your string:

 "did you know {the quick {brown\nfox} jumps over the lazy dog} is\na pangram?"
.match(/\{[^{}]+\}/)

Returns {brown\nfox}.

/\{[^{}]+\}/:

1. Match a {.
2. Match everything that's not a { or }.
3. Match a }

DEMO

This will work Try it

\{([^{]+?)\}