Can compare arrays

lib/model.js

@@ -131,9 +131,9 @@ function deepCopy (obj) {
 
 
 /**
- * Utility function for comparing things
- * Works for numbers, strings and booleans
+ * Utility functions for comparing things
  * Assumes type checking was already done (a and b already have the same type)
+ * compareNSB works for numbers, strings and booleans
  */
 function compareNSB (a, b) {
   if (a < b) { return -1; }
@@ -141,11 +141,25 @@ function compareNSB (a, b) {
   return 0;
 }
 
+function compareArrays (a, b) {
+  var i, comp;
+
+  for (i = 0; i < Math.min(a.length, b.length); i += 1) {
+    comp = compareThings(a[i], b[i]);
+
+    if (comp !== 0) { return comp; }
+  }
+
+  // Common section was identical, longest one wins
+  return compareNSB(a.length, b.length);
+}
+
+
 /**
  * Compare things
  * Things are defined as any native types (string, number, boolean, null, date) and objects
  * In the case of objects and arrays, we compare the serialized versions
- * If two objects dont have the same type, the (arbitrary) type hierarchy is: null, number, strings, boolean, dates, objects, arrays
+ * If two objects dont have the same type, the (arbitrary) type hierarchy is: null, number, strings, boolean, dates, arrays, objects
  * Return -1 if a < b, 1 if a > b and 0 if a = b (note that equality here is NOT the same as defined in areThingsEqual!)
  */
 function compareThings (a, b) {
@@ -168,6 +182,10 @@ function compareThings (a, b) {
   // Dates
   if (util.isDate(a)) { return util.isDate(b) ? compareNSB(a.getTime(), b.getTime()) : -1; }
   if (util.isDate(b)) { return util.isDate(a) ? compareNSB(a.getTime(), b.getTime()) : 1; }
+
+  // Arrays (first element is most significant and so on)
+  if (util.isArray(a)) { return util.isArray(b) ? compareArrays(a, b) : -1; }
+  if (util.isArray(b)) { return util.isArray(a) ? compareArrays(a, b) : 1; }
 }
 
 

test/model.test.js

@@ -415,6 +415,27 @@ describe('Model', function () {
       });
     });
 
+    it('Then arrays', function () {
+      var otherStuff = [{}, { hello: 'world' }]
+        , arrays = [[], ['yes'], ['hello', 5]]
+        ;
+
+      model.compareThings([], []).should.equal(0);
+      model.compareThings(['hello'], []).should.equal(1);
+      model.compareThings([], ['hello']).should.equal(-1);
+      model.compareThings(['hello'], ['hello', 'world']).should.equal(-1);
+      model.compareThings(['hello', 'earth'], ['hello', 'world']).should.equal(-1);
+      model.compareThings(['hello', 'zzz'], ['hello', 'world']).should.equal(1);
+      model.compareThings(['hello', 'world'], ['hello', 'world']).should.equal(0);
+
+      otherStuff.forEach(function (stuff) {
+        arrays.forEach(function (array) {
+          model.compareThings(array, stuff).should.equal(-1);
+          model.compareThings(stuff, array).should.equal(1);
+        });
+      });
+    });
+
   });   // ==== End of 'Comparing things' ==== //