If you have updated your npm to the latest version and tried installing the package using npm install moment—save you will see the package moment.js get saved in packages.json with a caret(^)prefix and in the previous version it was saved with tilde(~)prefix. You might think what is the difference between these symbols.
The tilde prefix simply indicates that the tilde (~) symbol will match the most recent patch version or the most recent minor version i.e. the middle number. For example, ~1.2.3 will match all 1.2.x versions but it will not match 1.3.0 or 1.3.x versions.
The caret indicates the first number i.e. the most recent major version. An example is in 1.x.x release the caret will update you and it will match with 1.3.0 but not 2.0.0.