Js regex allow optional line break and space indentation

Question

Some relative posts:


let s = `
%nav.cf
  %ul.cf
    %li
      %a{
        :href => "#"
      } Item 1
    %li
      %a{href => "#"} Item 2
    %li
      %a{:href => "#"} Item 2
    %li
      %a{:href => "#"} Item 3

  %a{:href => "#", :id => "openup"} MENU

%h1 Basic Responsive Menu
%p Playing around and learning HAML + SCSS - Basic Responsive Menu.
`;

s.replace(/\{?[\r\n]+.*\=\>(.*)\}/g, cd=>{
  console.log(cd);
});

/*
      %a{href => "#"}

      %a{:href => "#"}

      %a{:href => "#"}


  %a{:href => "#", :id => "openup"}
*/

s.replace(/\{?[\r\n]+.*\=\>(.*)[\s]+\}/g, cd=>{
  console.log(cd);
});
/*
{
        :href => "#"
      }
*/

I am writing an adopter for a template engine, basically I need to extract all the hash insides {} that must have a =>.

The expected result are all the commented values above. which the code either returns first or the second.

{
        :href => "#"
      }
%a{href => "#"}
%a{:href => "#"}
%a{:href => "#"}
 %a{:href => "#", :id => "openup"}

please have a look at the second expression, where I try to allow the optional line break and spaces indentation, I wonder why it gets rid of the unescaped hashes returned before.

anubhava · Accepted Answer · 2023-03-14T17:13:28.250

2

You don't need to use replace. Just use this regex for matching in MULTILINE mode

^[^{}\n]*{(?=[^}#]*#)[^}]*=>[^}]*}

RegEx Demo

Code:

let s = `
%nav.cf
  %ul.cf
    %li
      %a{
        :href => "#"
      } Item 1
    %li
      %a{href => "#"} Item 2
    %li
      %a{:href => "#"} Item 2
    %li
      %a{:href => "#"} Item 3

  %a{:href => "#", :id => "openup"} MENU

%h1 Basic Responsive Menu
%p Playing around and learning HAML + SCSS - Basic Responsive Menu.`;

console.log( s.match(/^[^{}\n]*{(?=[^}#]*#)[^}]*=>[^}]*}/gm) );

RegEx Details:

^: Start
[^{}\n]*: Match 0 or more of any characters that are not { and } and a line break
{: Match a {
(?=[^}#]*#): Lookahead to make sure that we have a # before matching }
[^}]*: Match 0 or more of any characters that are not }
=>: Match a =>
[^}]*: Match 0 or more of any characters that are not }
}: Match a }

edited Mar 14 '23 at 17:13

answered Mar 14 '23 at 16:19

anubhava

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Cheers, however I need to extract the first expression with line breaks and indentations as well. ^v^ – Weilory Mar 14 '23 at 16:23
Cab you edit the question and show your expected output separately from the big code block. – anubhava Mar 14 '23 at 16:25
1

Sure, have added that. – Weilory Mar 14 '23 at 16:27
ok check my updated answer now and new demo – anubhava Mar 14 '23 at 16:31
1

Thanks @Thefourthbird Yes I should have excluded `#` as well (edited) – anubhava Mar 14 '23 at 17:12

Js regex allow optional line break and space indentation

1 Answers1