fix componentjs/component#621

lib/remote.js

@@ -77,6 +77,46 @@ function Remote(options) {
  */
 
 Remote.prototype.resolve = function* (remotes, repo, ref) {
+  // TODO: this is ugly
+  if (typeof remotes === 'string') {
+    ref = repo;
+    repo = remotes;
+  } else if (Array.isArray(remotes) && !~remotes.indexOf(this.name)) {
+    // if the current remote is not in this list,
+    // then it's obviously not valid.
+    return;
+  }
+  var versions = yield* this.getAvailableVersions(remotes, repo, ref);
+
+  // TODO: this looks not good, should return null or something like that
+  if (versions == null) versions = ['master']; 
+
+  // add master, if there are no versions published
+  if (versions.length === 0) versions.push('master');
+
+  // TODO: are there use cases where ref is not defined?
+  var reference = ref || versions[0];
+
+  var json = yield* this.json(repo, reference);
+  if (json) return this;
+};
+
+Remote.prototype.isValid = function* (remotes, repo, ref) {
+  var versions = yield* this.getAvailableVersions(remotes, repo, ref);
+  if (versions == null) return false;
+  // return true if there are some version, or there are no version published (empty array)
+  return true;
+};
+
+/**
+ * There are two use cases for this function:
+ * 1. Just to check if a repo exist via isValid()
+ * 2. Get available versions
+ *
+ * @return {this}
+ * @api public
+ */
+Remote.prototype.getAvailableVersions = function* (remotes, repo, ref) {
   if (typeof remotes === 'string') {
     ref = repo;
     repo = remotes;
@@ -87,11 +127,7 @@ Remote.prototype.resolve = function* (remotes, repo, ref) {
   }
   // use latest tag, and if it's not available, then master
   var availableVersions = yield* this.versions(repo);
-  if (availableVersions == null || availableVersions.length == 0) {
-    availableVersions = ['master'];
-  }
-  var json = yield* this.json(repo, ref || availableVersions[0]);
-  if (json) return this;
+  return availableVersions;
 };
 
 /**
@@ -104,6 +140,11 @@ Remote.prototype.resolve = function* (remotes, repo, ref) {
  */
 
 Remote.prototype.versions = function* (repo) {
+  if (!repo) {
+    console.log("repo: "+repo);
+    console.log(new Error().stack);
+  }
+
   repo = repo.toLowerCase();
   var event = 'version:' + repo;
   var cache = this.c_versions;

lib/remotes.js

@@ -76,6 +76,33 @@ Remotes.prototype.use = function (remote) {
  * @api public
  */
 
+Remotes.prototype.check = function* (remotes, name, reference) {
+  var length = this.remotes.length;
+  if (!length) throw new Error('no remotes');
+
+  // resolve(name, [reference])
+  if (typeof remotes === 'string') {
+    reference = name;
+    name = remotes;
+    remotes = null;
+  }
+
+  remotes = remotes || this.remotes.map(toName);
+
+  // map to remote instances
+  var instances = remotes.map(function (name) {
+    return this.remote[name];
+  }, this).filter(Boolean);
+  remotes = instances.map(toName);
+
+  // loop through
+  for (var i = 0; i < instances.length; i++) {
+    if (yield* instances[i].isValid(remotes, name, reference)) {
+      return instances[i];
+    }
+  }
+};
+
 Remotes.prototype.resolve = function* (remotes, name, reference) {
   var length = this.remotes.length;
   if (!length) throw new Error('no remotes');
@@ -96,10 +123,11 @@ Remotes.prototype.resolve = function* (remotes, name, reference) {
   remotes = instances.map(toName);
 
   // loop through
-  for (var i = 0; i < instances.length; i++)
+  for (var i = 0; i < instances.length; i++) {
     if (yield* instances[i].resolve(remotes, name, reference))
       return instances[i];
-}
+  }
+};
 
 function toName(x) {
   return x.name;