package.json version中 ‘~‘ 和 ‘^‘ 的区别，

• ~version "Approximately equivalent to version" See npm semver - Tilde Ranges & semver (7). will update you to all future patch versions, without incrementing the minor version. ~1.2.3 will use releases from 1.2.3 to <1.3.0.

• ^version "Compatible with version" See npm semver - Caret Ranges & semver (7). will update you to all future minor/patch versions, without incrementing the major version. ^2.3.4 will use releases from 2.3.4 to <3.0.0.
• version Must match version exactly
• >version Must be greater than version
• >=version etc
• <version
• <=version
• 1.2.x 1.2.0, 1.2.1, etc., but not 1.3.0
• http://sometarballurl (this may be the URL of a tarball which will be downloaded and installed locally
• * Matches any version
• latest Obtains latest release

这些都是有效的：

{ "dependencies" :
  { "foo" : "1.0.0 - 2.9999.9999"
  , "bar" : ">=1.0.2 <2.1.2"
  , "baz" : ">1.0.2 <=2.3.4"
  , "boo" : "2.0.1"
  , "qux" : "<1.0.0 || >=2.3.1 <2.4.5 || >=2.5.2 <3.0.0"
  , "asd" : "http://asdf.com/asdf.tar.gz"
  , "til" : "~1.2"
  , "elf" : "~1.2.3"
  , "two" : "2.x"
  , "thr" : "3.3.x"
  , "lat" : "latest"
  , "dyl" : "file:../dyl"
  }
}

参考链接： 
https://docs.npmjs.com/files/package.json
https://docs.npmjs.com/misc/semver