regexp-dollar-in-replace.md

$ in the replace() Function

Sign	Description
$1	text matched in the 1st group
$2	text matched in the 2nd group
$n	text matched in the n-th group
$$	literal $ sign
$&	the matched text
$`	text placed before the matched one
$'	text placed after the matched one

Example #1

var str = '$> AB12@CD34 !';
var re = /(\w+\d+)@(\w+\d+)/g;

str.replace(re, "before($`) matched($&) after($')");
// "$> before($> ) matched(AB12@CD34) after( !) !"

// $> - the original non-replaced $>
// before($> ) - the text placed before the matched one
// matched(AB12@CD34) - the matched text
// after( !) - the text placed after the matched one
//  ! - the original non-replaced  !

Example #2

var str = '$> AB12@CD34 !';
var re = /(\w+\d+)/g;

str.replace(re, "before($`) matched($&) after($')");
// "$> before($> ) matched(AB12) after(@CD34 !)@before($> AB12@) matched(CD34) after( !) !"

// $> - the original non-replaced $>
// before($> ) - the text placed before the first matched text
// matched(AB12) - the first matched text
// after(@CD34 !) - the text placed after the first matched text
// @ - the original non-replaced @
// before($> AB12@) - the text placed before the second matched text
// matched(CD34) - the second matched text
// after( !) - the text placed after the second matched text
//  ! - the original non-replaced  !