如何在单词的开头和结尾替换字符？

Question

For example:

var string = This is a *piece* of text.

I could do:

string.replace(/\*/g, <em>)

However, I would get this: <em>piece<em> . And what I want to get is this: <em>piece</em> .

How to modify this code so I can detect the * character at the beginning and end of a word?

Answer 1

You can use capturing groups like this:

 var string = 'This is a *piece* of text.' var r = string.replace(/\\*([^\\*]+)\\*/, (m, m1) => `<em>${m1}</em>`) console.log(r) 

Even better you could build regex on the fly with any boundry character

 const parseChar = x => node => str => { const re = new RegExp(`\\\\${x}([^\\\\${x}]+)\\\\${x}`) return str.replace(re, (_, m) => `<${node}>${m}</${node}>` ) } var string = 'This is a *piece* of text.' var r = parseChar('*')('em')(string) console.log(r) 

Answer 2

You could use replace with a first capturing group where you would capture not a * using a negated character class ([^*]+) and use the g global flag to replace all of them.

\\*([^*]+)\\*

That would match

• \\* Match *
• ([^*]+) Capture in a group matching not a * one or more times or else you might end up with <em></em>
• \\* Match *

 var string = 'This is a *piece* of text and *piece*'; string = string.replace(/\\*([^*]+)\\*/g, "<em>$1</em>"); console.log(string);