Regular Expressions for manipulating linebreaks (needs review)

linebreaks.js

var test_str = 'test\n\n\nha\n\n\n\n\n\n\n\nbla\nbla\n';
// Replace more than two \n with two \n
var data = test_str.replace(new RegExp('(\n){3,}', 'gim') , '\n\n');
// normalize line endings to \n, because \r is not recognized as "end of line"
data = data.replace (/\s*\R/g, "\n");
// remove leading and trailing whitespace
data = data.replace (/^\s*|[\t ]+$/gm, "");