I try to remove everything before first timestamp in .vtt file.
I made something .replace(/(.*)\s+1/gmi, '') but it select "1" as well. My expecting is to select everything except "1" which should be a first line in file.
WEBVTT
1
00:00:00.080 --> 00:00:05.930
Lorem Ipsum is simply dummy text of the printing and typesetting industry.
2
00:00:05.930 --> 00:00:07.430
Lorem Ipsum is simply dummy text of the printing and typesetting industry.
3
00:00:07.430 --> 00:00:13.130
Lorem Ipsum is simply dummy text of the printing and typesetting industry.
1
00:00:00.080 --> 00:00:05.930
Lorem Ipsum is simply dummy text of the printing and typesetting industry.
2
00:00:05.930 --> 00:00:07.430
Lorem Ipsum is simply dummy text of the printing and typesetting industry.
3
00:00:07.430 --> 00:00:13.130
Lorem Ipsum is simply dummy text of the printing and typesetting industry.
Use
.replace(/^.*\s+(?=^1$)/m, '')
I removed global flag because this expression must remove from start of string only. m is preserved, it makes both anchors be applied at start and end of a line.
Capturing parentheses are not necessary.
(?=^1$) ensures the match comes before a line with a single 1 on it.
See regex proof.