A good rule of thumb is, specify the version that can pull the latest version, but is backward compatible with earlier versions, so that you get small updates and bug fixes, but not a version that can break your project.
The version number has a meaning. And it is written by the founder and CEO of GitHub, so you may want to take a look.
^ means "compatible". In the above case, it means
16.x.x, but not
17.0 may break your project, and you want to be careful about it. (that's why in the Gemfile case below, the operator is called a "pessimistic operator".) If a programmer is optimistic, it can be written as
16.14.0 or above, including
23.0. That might be "too optimistic".
gem 'sqlite3', '~> 1.4'
~> has 3 names: pessimistic operator, twiddle-wakka, and eating bacon.
Note that the first character is a tilde:
In some font, it can look like a hyphen.
The above means
1.x.x, but not
Note that you can't write
gem 'sqlite3', '~> 1.4.0'
to mean the same thing. Because that means in
1.4.x but not
Gemfile, to achieve what
package.json is doing, it can be:
gem 'sqlite3', '~> 1.4', '>= 1.4.1'
meaning at least
1.x but not
2.0. The reason you want to be specific about
1.4.1 may be due to a bug fix in
1.4.1 or any other reasons.
Reference: dependencies in
Level up every day