^0.x.y always equivalent to =0.x.y

More in line with specification at http://semver.org

README.md

@@ -66,11 +66,11 @@ The following range styles are supported:
   prerelease) will be supported up to, but not including, the next
   major version (or its prereleases). `1.5.1` will satisfy `^1.2.3`,
   while `1.2.2` and `2.0.0-beta` will not.
-* `^0.1.3` := `>=0.1.3-0 <0.2.0-0` "Compatible with `0.1.3`". `0.x.x` versions are
-  special: the first non-zero component indicates potentially breaking changes,
-  meaning the caret operator matches any version with the same first non-zero
-  component starting at the specified version.
-* `^0.0.2` := `=0.0.2` "Only the version `0.0.2` is considered compatible"
+* `^0.1.3` := `0.1.3` "Compatible with `0.1.3`". `0.x.x` versions are
+  special: since the semver spec specifies that `0.x.x` versions make
+  no stability guarantees, only the version specified is considered
+  valid.
+* `^0.0.2` := `0.0.2` "Only the version `0.0.2` is considered compatible"
 * `~1.2` := `>=1.2.0-0 <1.3.0-0` "Any version starting with `1.2`"
 * `^1.2` := `>=1.2.0-0 <2.0.0-0` "Any version compatible with `1.2`"
 * `1.2.x` := `>=1.2.0-0 <1.3.0-0` "Any version starting with `1.2`"

semver.js

@@ -369,7 +369,7 @@ SemVer.prototype.inc = function(release) {
       // If this is already a prerelease, it will bump to the next version
       // drop any prereleases that might already exist, since they are not
       // relevant at this point.
-      this.prerelease.length = 0
+      this.prerelease.length = 0;
       this.inc('patch');
       this.inc('pre');
       break;
@@ -770,6 +770,11 @@ function replaceCaret(comp, loose) {
   return comp.replace(r, function(_, M, m, p, pr) {
     debug('caret', comp, _, M, m, p, pr);
     var ret;
+    if (pr) {
+      if (pr.charAt(0) !== '-')
+        pr = '-' + pr;
+    } else
+      pr = '';
 
     if (isX(M))
       ret = '';
@@ -780,30 +785,14 @@ function replaceCaret(comp, loose) {
         ret = '>=' + M + '.' + m + '.0-0 <' + M + '.' + (+m + 1) + '.0-0';
       else
         ret = '>=' + M + '.' + m + '.0-0 <' + (+M + 1) + '.0.0-0';
-    } else if (pr) {
-      debug('replaceCaret pr', pr);
-      if (pr.charAt(0) !== '-')
-        pr = '-' + pr;
-      if (M === '0') {
-        if (m === '0')
-          ret = '=' + M + '.' + m + '.' + p + pr;
-        else
-          ret = '>=' + M + '.' + m + '.' + p + pr +
-                ' <' + M + '.' + (+m + 1) + '.0-0';
-      } else
-        ret = '>=' + M + '.' + m + '.' + p + pr +
-              ' <' + (+M + 1) + '.0.0-0';
-    } else {
-      if (M === '0') {
-        if (m === '0')
-          ret = '=' + M + '.' + m + '.' + p;
-        else
-          ret = '>=' + M + '.' + m + '.' + p + '-0' +
-                ' <' + M + '.' + (+m + 1) + '.0-0';
-      } else
-        ret = '>=' + M + '.' + m + '.' + p + '-0' +
-              ' <' + (+M + 1) + '.0.0-0';
-    }
+    } else if (M === '0')
+      ret = '=' + M + '.' + m + '.' + p + pr;
+    else if (pr)
+      ret = '>=' + M + '.' + m + '.' + p + pr +
+            ' <' + (+M + 1) + '.0.0-0';
+    else
+      ret = '>=' + M + '.' + m + '.' + p + '-0' +
+            ' <' + (+M + 1) + '.0.0-0';
 
     debug('caret return', ret);
     return ret;

test/index.js

@@ -410,7 +410,7 @@ test('\nvalid range test', function(t) {
     ['^1.2', '>=1.2.0-0 <2.0.0-0'],
     ['^0.0.1', '0.0.1'],
     ['^0.0.1-beta', '0.0.1-beta'],
-    ['^0.1.2', '>=0.1.2-0 <0.2.0-0'],
+    ['^0.1.2', '0.1.2'],
     ['^1.2.3', '>=1.2.3-0 <2.0.0-0'],
     ['^1.2.3-beta.4', '>=1.2.3-beta.4 <2.0.0-0'],
     ['<1', '<1.0.0-0'],