Is there a way to troubleshoot and adjust this regex to accurately replace asterisks within words?

Question

Is there a way to troubleshoot and adjust this regex to accurately replace asterisks within words?

I've been experimenting with regex. I came up with a regex pattern that converts * into <em>, similar to Markdown:

el = el.replace(/\*\b/g, '<em>')
el = el.replace(/\b\*|(\.|\,|\?|\!|\*|---|\.\.\.\s)\*/g, '$1</em>')

It works well in most cases. However, things get messy when you apply this regex to the following text:

Chicken teriy*ai*ki, r*ai*men noodles, spaghetti a la moneg*ai*sque.

It produces this result:

Chicken teriy<em>ai<em>ki, r<em>ai<em>men noodles, spaghetti a la moneg<em>ai<em>sque. And wait for me, often falling asleep.</em></em></em></em></em></em>

Is there a way to modify this regex so it gives an output more like this:

 Chicken teriy<em>ai</em>ki, r<em>ai</em>men noodles, spaghetti a la moneg<em>ai</em>sque. And wait for me, often falling asleep.

javascript regex markdown

Answer 1

Answer №1

To combine the two branches in your second regex, you can merge them since they both end with the \* pattern. For example, you could use (\b|\.|,|\?|!|\*|---|\.{3}\s)\* (you could also simplify it further by merging the single character alternatives like \.|,|\?|!|\* into [.,?!*]) and then implement the following:

var s = "Chicken teriy*ai*ki, r*ai*men noodles, spaghetti a la moneg*ai*sque.";
console.log(
  s.replace(/\*\b([^]*?)(\b|[.,?!*]|---|\.{3}\s)\*/g, '<em>$1$2</em>') 
)

Details

\*\b - Represents a * followed by a word character (letter, digit, or underscore).
([^]*?) - Group 1: Any 0+ characters, as few as possible (can be replaced with [\s\S] / [\d\D] / [\w\W] for more portability), up to the leftmost occurrence of
(\b|[.,?!*]|---|\.{3}\s) - Word boundary, ., ,, ?, !, *, ---, ... + whitespace
\* - Represents a * character.

Answer 2

To combine the two branches in your second regex, you can merge them since they both end with the \* pattern. For example, you could use (\b|\.|,|\?|!|\*|---|\.{3}\s)\* (you could also simplify it further by merging the single character alternatives like \.|,|\?|!|\* into [.,?!*]) and then implement the following:

var s = "Chicken teriy*ai*ki, r*ai*men noodles, spaghetti a la moneg*ai*sque.";
console.log(
  s.replace(/\*\b([^]*?)(\b|[.,?!*]|---|\.{3}\s)\*/g, '<em>$1$2</em>') 
)

Details

\*\b - Represents a * followed by a word character (letter, digit, or underscore).
([^]*?) - Group 1: Any 0+ characters, as few as possible (can be replaced with [\s\S] / [\d\D] / [\w\W] for more portability), up to the leftmost occurrence of
(\b|[.,?!*]|---|\.{3}\s) - Word boundary, ., ,, ?, !, *, ---, ... + whitespace
\* - Represents a * character.

Answer 3

Answer №2

Here is a solution that utilizes the use of regular expressions to wrap specific characters in * signs with em tags. Please note that this transformation will be applied universally to the entire input string provided.

 let str = "enclose these words with * symbols to emphasize them"
 str.replace(/\*(\w+)\*/g, "<em>$1</em>")

Answer 4

Here is a solution that utilizes the use of regular expressions to wrap specific characters in * signs with em tags. Please note that this transformation will be applied universally to the entire input string provided.

 let str = "enclose these words with * symbols to emphasize them"
 str.replace(/\*(\w+)\*/g, "<em>$1</em>")

Answer 5

Answer №3

Pattern to use: \*([\w ^?.]*?)\*

Replacement code: <em>$1<\em>

el = el.replace(/\*([\w ^?.]*?)\*/g, '<em>$1<\em>')

Explore the Regex

Answer 6

Pattern to use: \*([\w ^?.]*?)\*

Replacement code: <em>$1<\em>

el = el.replace(/\*([\w ^?.]*?)\*/g, '<em>$1<\em>')

Explore the Regex

Is there a way to troubleshoot and adjust this regex to accurately replace asterisks within words?

Answer №1

Answer №2

Answer №3

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