how to replace \n from string js code example

Example 1: javascript replace line breaks with 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"

Example 2: javascript replace \n

var r = "I\nam\nhere";
var s = r.replace(/\n/g,' ');