Javascript: Insert text at specified line

Question

I am kind of new to javascript, but I was looking to see if it was possible to add a line of text to a file at a specified position? ie every file needs to have the same text inserted at line no. 3

Someone suggested "split by line feed, add data, then rejoin", but i have no clue how to do that. Just looking for somewhere to get started or pointed in the right diretion.

Answer 1

Split by line feed:

data = data.split(/\r?\n/);

Add data:

data = data.splice(2, 0, new_data);

Rejoin:

data = data.join("\r\n");