What’s the difference between tilde(~) and caret(^) in package.json?

After I upgraded to latest stable node and npm, I tried npm install moment --save. It saves the entry in the package.json with the caret(^) prefix. Previously, it was a tilde(~) prefix.

  1. Why are these changes made in npm?
  2. What is the difference between tilde(~) and caret(^)?
  3. What is the advantages over others?

In the simplest terms, the tilde matches the most recent minor version
(the middle number). ~1.2.3 will match all 1.2.x versions but will
miss 1.3.0.

The caret, on the other hand, is more relaxed. It will update you to
the most recent major version (the first number). ^1.2.3 will match
any 1.x.x release including 1.3.0, but will hold off on 2.0.0.

http://fredkschott.com/post/2014/02/npm-no-longer-defaults-to-tildes/