Regex Replace Enters Between Quotes

How do i replace all enters between two quotes in a text file. The first quote is always preceded by a tab or it is the first character in the row (csv file). I tried the following

Solution 1:

With Javascript replace you can use a function as replacement.

var str = 'foo \n"a\n" bar\n';

str = str.replace(/"[^"]+"/g, function(m) {
 return m.replace(/\n/g, ' ');
});

console.log(str);

The regex "[^"]+" will match quoted stuff with one or more non-quotes in between.

Add conditions such as tab or start to the pattern as needed: (?:\t|^)"[^"]+"

Solution 2:

\n(?=[^"]*"(?:[^"]*"[^"]*")*[^"]*$)

You can use this and replace by empty string.

See Demo

var re =/\n(?=[^"]*"(?:[^"]*"[^"]*")*[^"]*$)/g; 
var str = 'xx "xx \nxx \nxx" \nxx \n"xx"\nxx \nxx\n"xxx xxx \nxx"';
var subst = ''; 

var result = str.replace(re, subst);