Index: node_modules/semver/functions/diff.js
===================================================================
--- node_modules/semver/functions/diff.js	(revision 81bc7da776d8cda42939ef4ab350c88d13b4941f)
+++ node_modules/semver/functions/diff.js	(revision 81bc7da776d8cda42939ef4ab350c88d13b4941f)
@@ -0,0 +1,60 @@
+'use strict'
+
+const parse = require('./parse.js')
+
+const diff = (version1, version2) => {
+  const v1 = parse(version1, null, true)
+  const v2 = parse(version2, null, true)
+  const comparison = v1.compare(v2)
+
+  if (comparison === 0) {
+    return null
+  }
+
+  const v1Higher = comparison > 0
+  const highVersion = v1Higher ? v1 : v2
+  const lowVersion = v1Higher ? v2 : v1
+  const highHasPre = !!highVersion.prerelease.length
+  const lowHasPre = !!lowVersion.prerelease.length
+
+  if (lowHasPre && !highHasPre) {
+    // Going from prerelease -> no prerelease requires some special casing
+
+    // If the low version has only a major, then it will always be a major
+    // Some examples:
+    // 1.0.0-1 -> 1.0.0
+    // 1.0.0-1 -> 1.1.1
+    // 1.0.0-1 -> 2.0.0
+    if (!lowVersion.patch && !lowVersion.minor) {
+      return 'major'
+    }
+
+    // If the main part has no difference
+    if (lowVersion.compareMain(highVersion) === 0) {
+      if (lowVersion.minor && !lowVersion.patch) {
+        return 'minor'
+      }
+      return 'patch'
+    }
+  }
+
+  // add the `pre` prefix if we are going to a prerelease version
+  const prefix = highHasPre ? 'pre' : ''
+
+  if (v1.major !== v2.major) {
+    return prefix + 'major'
+  }
+
+  if (v1.minor !== v2.minor) {
+    return prefix + 'minor'
+  }
+
+  if (v1.patch !== v2.patch) {
+    return prefix + 'patch'
+  }
+
+  // high and low are prereleases
+  return 'prerelease'
+}
+
+module.exports = diff