check that they type of a value is a boolean, not just that it is cur…

…rently set to a boolean

index.js

@@ -65,6 +65,25 @@ module.exports = function (args, opts) {
             setKey(argv, x.split('.'), value);
         });
     }
+
+    function setKey (obj, keys, value) {
+        var o = obj;
+        keys.slice(0,-1).forEach(function (key) {
+            if (o[key] === undefined) o[key] = {};
+            o = o[key];
+        });
+
+        var key = keys[keys.length - 1];
+        if (o[key] === undefined || flags.bools[key]) {
+            o[key] = value;
+        }
+        else if (Array.isArray(o[key])) {
+            o[key].push(value);
+        }
+        else {
+            o[key] = [ o[key], value ];
+        }
+    }
 
     for (var i = 0; i < args.length; i++) {
         var arg = args[i];
@@ -192,25 +211,6 @@ function hasKey (obj, keys) {
     return key in o;
 }
 
-function setKey (obj, keys, value) {
-    var o = obj;
-    keys.slice(0,-1).forEach(function (key) {
-        if (o[key] === undefined) o[key] = {};
-        o = o[key];
-    });
-
-    var key = keys[keys.length - 1];
-    if (o[key] === undefined || typeof o[key] === 'boolean') {
-        o[key] = value;
-    }
-    else if (Array.isArray(o[key])) {
-        o[key].push(value);
-    }
-    else {
-        o[key] = [ o[key], value ];
-    }
-}
-
 function isNumber (x) {
     if (typeof x === 'number') return true;
     if (/^0x[0-9a-f]+$/i.test(x)) return true;