| 5878 | |
| 5879 | exports.diff = diff |
| 5880 | function diff (version1, version2) { |
| 5881 | if (eq(version1, version2)) { |
| 5882 | return null |
| 5883 | } else { |
| 5884 | var v1 = parse(version1) |
| 5885 | var v2 = parse(version2) |
| 5886 | var prefix = '' |
| 5887 | if (v1.prerelease.length || v2.prerelease.length) { |
| 5888 | prefix = 'pre' |
| 5889 | var defaultResult = 'prerelease' |
| 5890 | } |
| 5891 | for (var key in v1) { |
| 5892 | if (key === 'major' || key === 'minor' || key === 'patch') { |
| 5893 | if (v1[key] !== v2[key]) { |
| 5894 | return prefix + key |
| 5895 | } |
| 5896 | } |
| 5897 | } |
| 5898 | return defaultResult // may be undefined |
| 5899 | } |
| 5900 | } |
| 5901 | |
| 5902 | exports.compareIdentifiers = compareIdentifiers |
| 5903 | |