How to replace URLs not within a href tag in javascript
javascript, regex, regex-negation
Solution
Without trying to analyze the complex regex and function above, here is an example implementation using a toy url matching pattern to illustrate a method of making such replacements
var str = ' www.stackoverflow.com <a href="http://www.somesite.com">somesite</a> www.othersite.org '
rex = /(<a href=")?(?:https?:\/\/)?(?:\w+\.)+\w+/g;
str = str.replace( rex, function ( $0, $1 ) {
return $1 ? $0 : '<a href="' + $0 + '">' + $0 + '</a>';
});
You can alter the url matching pattern and insert e.g. `\s*` as required.
Problem
I have a situation where I have text which contains URL links. The links are in 2 forms - www.stackoverflow.com - <a href="http://www.stackoverflow.com">Stack over flow</a> I am trying to create a simple function that uses regex that will wrap all links of type 1 with A HREF tag but leaving the other ones already wrapped a lone. I have something like this but not successful. ``` function replaceURLWithHTMLLinks(text) { var exp = /(<(\s*)a(\s)*href.*>.*<\/(\s)*a(\s*)>)/ig; var matches = exp.exec(text); for(var i=0; i < matches.length; i++) { var line = matches[i]; if(!exp.test(line)) { var exp2 = /(\b(?:(?:(?:https?|ftp|file):\/\/|www\.|ftp\.)[-A-Z0-9+&@#\/%?=~_|$!:,.;]*[-A-Z0-9+&@#\/%=~_|$])|”(?:(?:https?|ftp|file):\/\/|www\.|ftp\.)[^"\r\n]+”?|’(?:(?:https?|ftp|file):\/\/|www\.|ftp\.)[^'\r\n]+’?)/ig; text = text.replace("http://",""); text = text.replace(exp2, "<a href=http://$1>$1</a>"); } } return text; } ``` It's not working but hoping someone could fix it :) EDIT The solution that fixed it, with the help of @MikeM answer ``` function replaceLinksSO(text) { rex = /(<a href=")?(?:https?:\/\/)?(?:(?:www)[-A-Za-z0-9+&@#\/%?=~_|$!:,.;]+\.)+[-A-Za-z0-9+&@#\/%?=~_|$!:,.;]+/ig; return text.replace(rex, function ( $0, $1 ) { if(/^https?:\/\/.+/i.test($0)) { return $1 ? $0: '<a href="'+$0+'">'+$0+'</a>'; } else { return $1 ? $0: '<a href="http://'+$0+'">'+$0+'</a>'; } }); } ```