CODEWITHSUNDEEP
javascriptregexcomments
user18472307
user18472307

Reputation:

Can you replace an inline comment in a string?

I´m writing a program to scan code files and have to remove comments first. Single- and Multiline comments.

The single line comments seem to work out perfectly but somehow the multiline part doesn´t seem to work properly.

It does find the multiline comment but doesn´t replace it. when using

outputCode.replace(multilineComment, '');

my function:

  // remove all comments by removing everything between the matches indexes and the next endOfCommentRegex
  const removeAllComments = async (endOfCommentRegex: RegExp, matches: RegExpMatchArray[]) => {
    let comments: string[] = [];
    matches.forEach(async match => {
      // find the next endOfCommentRegex after the match.index
      const endOfCommentMatch = outputCode.slice(match.index).match(endOfCommentRegex);
      if (endOfCommentMatch) {
        // store everything between the match.index and the endOfCommentMatch.index in a variable if the char at match.index - 1 is not a : (for https://...)
        if (outputCode.charAt(match.index! - 1) !== ':') {
          comments.push(outputCode.slice(match.index, match.index! + endOfCommentMatch.index! + 2));
        }
      }
    });
    // remove all comments from the outputCode
    comments.forEach(comment => {
      outputCode = outputCode.replace(comment, '');
    });
  };

and call the function like so:

// check for all multiline comments
const multiMatches = [...outputCode.matchAll(/\/\*/g)];
if (multiMatches.length !== 0) {
  await removeAllComments(/\*\//, multiMatches);
}

expected output: the file(string)content without the multiline in it.

current output: file(string)content + multilineComment + file(string)content

I have no idea, why it cocatinates the string that weird instead of simply replacing the comment.

Any idea what could be wrong here?

edit: like I said, it does find the multiline comment and safes it in the comments array like so: "/* multiline dummy comment */"

Upvotes: 0

Views: 261

Answers (1)

thisistemporary
thisistemporary

Reputation: 137

This regex works for me /(\/\*(.*?\n*)*?\*\/)/g

  • / - start of regex
  • ( - start of capturing group
  • \ / - escaped / (matches /)
  • \ * - escaped * (matches *)
  • ( - start of capturing group
  • .*? - any character (optional, lazy - matches as few as possible)
  • \n* - line break (optional)
  • )*? - end of capturing group (optional, lazy - matches as few as possible)
  • \ * - escaped * (matches *)
  • \ / - escaped / (matches /)
  • ) - end of capturing group
  • / - end of regex
  • g - global flag
let reg = /(\/\*(.*?\n*)*?\*\/)/g;
outputCode = outputCode.replace(reg, '');

Upvotes: 1

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