What is the meaning of the 'g' flag in regular expressions?

Question

What is the meaning of the g flag in regular expressions?

What is is the difference between /.+/g and /.+/?

Answer 1

1. g -> returns all matches
2. without g -> returns first match

example:

1. '1 2 1 5 6 7'.match(/\d+/) returns ["1", index: 0, input: "1 2 1 5 6 7", groups: undefined]. As you see we can only take first match "1".
2. '1 2 1 5 6 7'.match(/\d+/g) returns an array of all matches ["1", "2", "1", "5", "6", "7"].

Answer 2

G in regular expressions is a defines a global search, meaning that it would search for all the instances on all the lines.

Answer 3

g is the global search flag.

The global search flag makes the RegExp search for a pattern throughout the string, creating an array of all occurrences it can find matching the given pattern.

So the difference between /.+/g and /.+/ is that the g version will find every occurrence instead of just the first.