Regex & Javascript : match a bloc of text only if the bloc is not surround by a specific string

Given this multi-line string :

  ```    +++ foo        The bloc        1    +++    ```      +++ foo        The         b        l        o        c 2    +++      +++ foo        The bloc 3    +++      ```    +++ foo        the bloc 4    +++    ```  

I created a regex for get the content between '+++ foo' and '+++'. All works fine :

https://regex101.com/r/HpEGen/3

Now I want capture only blocs not surrounded by two triple backtricks.
In my example, only blocs 2 and 3 must be captured because they aren't surrounded by triple backtricks.

I tried to use the Negative Lookahead assertion like this :

(?!```\n)(\+\+\+)(?: *)foo\n([\s\S]*?)\n(?:)\1

https://regex101.com/r/HpEGen/4/

But I capture the 4 groups and I don't understand why...

Thanks for any help :)

https://stackoverflow.com/questions/65571583/regex-javascript-match-a-bloc-of-text-only-if-the-bloc-is-not-surround-by-a January 05, 2021 at 08:14AM