codekingpro/portable-devtools

1'use strict'
2
3const parse = require('./parse.js')
4
5const diff = (version1, version2) => {
6  const v1 = parse(version1, null, true)
7  const v2 = parse(version2, null, true)
8  const comparison = v1.compare(v2)
9
10  if (comparison === 0) {
11    return null
12  }
13
14  const v1Higher = comparison > 0
15  const highVersion = v1Higher ? v1 : v2
16  const lowVersion = v1Higher ? v2 : v1
17  const highHasPre = !!highVersion.prerelease.length
18  const lowHasPre = !!lowVersion.prerelease.length
19
20  if (lowHasPre && !highHasPre) {
21    // Going from prerelease -> no prerelease requires some special casing
22
23    // If the low version has only a major, then it will always be a major
24    // Some examples:
25    // 1.0.0-1 -> 1.0.0
26    // 1.0.0-1 -> 1.1.1
27    // 1.0.0-1 -> 2.0.0
28    if (!lowVersion.patch && !lowVersion.minor) {
29      return 'major'
30    }
31
32    // If the main part has no difference
33    if (lowVersion.compareMain(highVersion) === 0) {
34      if (lowVersion.minor && !lowVersion.patch) {
35        return 'minor'
36      }
37      return 'patch'
38    }
39  }
40
41  // add the `pre` prefix if we are going to a prerelease version
42  const prefix = highHasPre ? 'pre' : ''
43
44  if (v1.major !== v2.major) {
45    return prefix + 'major'
46  }
47
48  if (v1.minor !== v2.minor) {
49    return prefix + 'minor'
50  }
51
52  if (v1.patch !== v2.patch) {
53    return prefix + 'patch'
54  }
55
56  // high and low are prereleases
57  return 'prerelease'
58}
59
60module.exports = diff
61