Question

Is it possible to join array elements with a regex? If so, how do I achieve these requirements?

• Every element should be joined with a spacing character unless it is an empty element.
• Empty array elements should be joined with a new line character (\n).

That means that this:

["Hello, this is a sentence.", "This is another sentence.", "", "", "Then, there are 2 new lines.","","Then just one new line."]

Should be converted with .join to this:

Hello, this is a sentence. This is another sentence.

Then, there are 2 new lines.
Then just one new line.

Answer 1

var string = "";

for(var index = 0; index < elements.length; index++) {
    var lastElement = elements[index -1];
    string += elements[index] !== "" ? (lastElement && lastElement !== ""? " " + elements[index] : elements[index]) : "\n";
}
console.log(string);

DEMO