JavaScript замените Newline на BR
function nl2br(str){
return str.replace(/(?:\r\n|\r|\n)/g, '<br>');
}
var stringWithNewLines= `Well this is a
a very broken
sentance`;
var stringWithBrs=nl2br(stringWithNewLines);
// stringWithBrs= "Well this is a<br>a very <br>broken<br>sentance"
Grepper