仅当两者之间存在某些文本时，正则表达式才匹配星号

Question

I have a regex pattern that detects the whole pattern, that is, asterisks along with the text in between.

Pattern: (\*|__)(.*?)\1

I want it to only match the asterisks, when the words are present in between. Example:

*This is one* This is some other text *New word* Another text another* and there is some more text

• Asterisks of This is one should be detected;
• Asterisks of New word should be detected;
• Last asterisk shouldn't be detected, as it doesn't have any closing one.

I tried several ways, but couldn't find a way, in which the middle words are not detected and only the asterisk.

Programming Language: Typescript (Angular)

Example 2:

*Project Name:* This is some other text *New word* Another text another and there is some more text

Answer 1

You can use

/(\*|__)(?!\s)(.+?)(?<!\s)\1/g

See the regex demo . Since you want to actually enclose * with tags, you may use the <i>$2</i> replacement pattern where $2 is a backreference to the Group 2 value.

Details :

• (\*|__) - Group 1: * or __
• (?!\s) - no whitespace is allowed immediately to the right of the current location
• (.+?) - Group 2: any one or more chars other than line break chars as few as possible
• (?<!\s) - no whitespace is allowed immediately on the left of the current location
• \1 - the same value as in Group 1 ( * or __ ).

See the JavaScript demo:

 let text = '*This is one* This is some other text *New word* Another text another* and there is some more text **'; text = text.replace(/(\*|__)(?.\s)(?+?)(,<;\s)\1/g. '<i>$2</i>'); console.log(text);