diff --git a/lib/Package.js b/lib/Package.js
index df201e1..c7ab4c7 100644
--- a/lib/Package.js
+++ b/lib/Package.js
@@ -270,10 +270,11 @@ Package.prototype.resolveDependencies = function(callback) {
  * @return {Array} An array representing a list of NPM package dependencies
  */
 Package.prototype.generateDependencyAST = function() {
+    var self = this;
     var dependencies = [];
 
-    for(var dependencyName in this.providedDependencies) {
-        var dependency = this.providedDependencies[dependencyName];
+    Object.keys(self.providedDependencies).sort().forEach(function(dependencyName) {
+        var dependency = self.providedDependencies[dependencyName];
 
         // For each dependency, refer to the source attribute set that defines it
         var ref = new nijs.NixAttrReference({
@@ -297,7 +298,7 @@ Package.prototype.generateDependencyAST = function() {
         }
 
         dependencies.push(dependencyExpr);
-    }
+    });
 
     if(dependencies.length == 0) {
         return undefined; // If no dependencies are required, simply compose no parameter. Though not mandatory, it improves readability of the generated expression
diff --git a/lib/SourcesCache.js b/lib/SourcesCache.js
index 5a75231..09bf538 100644
--- a/lib/SourcesCache.js
+++ b/lib/SourcesCache.js
@@ -33,12 +33,13 @@ SourcesCache.prototype.addSource = function(source) {
  * @see NixASTNode#toNixAST
  */
 SourcesCache.prototype.toNixAST = function() {
+    var self = this;
     var ast = {};
 
-    for(var identifier in this.sources) {
-        var source = this.sources[identifier];
+    Object.keys(self.sources).sort().forEach(function(identifier) {
+        var source = self.sources[identifier];
         ast[identifier] = source.toNixAST();
-    }
+    });
 
     return ast;
 };