string regex replace in node js

Question

I'm having the below string in my node js.

var textToReplace = "Your <b class =\"b_1\">1</b> payment due is $4000.Your 
<b class =\"b_1\">2</b> payment due is $3500. Your <b class =\"b_1\">3</b> 
payment due is $5000.";

Here I want to replace <b class =\"b_1\">*</b> with ''. The output is Your 1 payment due is $4000.Your 2 payment due is $3500. Your 3 payment due is $5000..

If this is a normal replace I wouldn't have had any problem, but here I think the best way to replace is by using Regex. This is where I'm confused. In java we have a stringVariableName.replaceAll() method. please let me know how can I do this.

Thanks

Answer 1

var newString = textToReplace.replace(/<b.*?>(.*?)<\/b>/g, '$1');

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Explanation:

<b.*?> : matches the <b ...> opening tag (using the non-greedy quantifier to match as few as possible)
(.*?)  : matches the content of the <b></b> tag (should be grouped so it will be used as a replacement text), it uses the non-greedy quantifier too.
<\/b>  : matches the closing tag
g      : global modifier to match as many as possible

then we replace the whole match with the first captured group $1 which represents the content of the <b></b> tag.

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Example:

var str = "Your <b class =\"b_1\">1</b> payment due is $4000.Your <b class =\"b_1\">2</b> payment due is $3500. Your <b class =\"b_1\">3</b> payment due is $5000.";

var newString = str.replace(/<b.*?>(.*?)<\/b>/g, "$1");

console.log(newString);

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Regex101 example.