表达式在每行末尾添加逗号。 虽然不应该做最后一行

Question

I have this pattern which works well for adding a comma to the end of every line.

str.replace(/(.+)\s*?($|\n)/gm, "$1, $2")

But I cannot understand how to change it so that it will not put a comma on the last line. Especially considering the last line could end in a line break. I guess I could search for the comma after the replace is done and just remove the last comma, but that seems sort of weak. Is there some way I can change this pattern so that it never appends a comma to the last line?

Answer 1

Just remove the $ from there, and add it as negative look ahead after \\n :

str.replace(/(.+)\s*?(\n(?!$))/gm, "$1, $2")

This will only add a comma before \\n if it is not at the end of the string.

Answer 2

Why not think in a bit different and very easy :

\\r?\\n(.+)