added unit testing, and started implementing unit tests...phew

node_modules/mixin-deep/index.js

@@ -0,0 +1,53 @@
+'use strict';
+
+var isExtendable = require('is-extendable');
+var forIn = require('for-in');
+
+function mixinDeep(target, objects) {
+  var len = arguments.length, i = 0;
+  while (++i < len) {
+    var obj = arguments[i];
+    if (isObject(obj)) {
+      forIn(obj, copy, target);
+    }
+  }
+  return target;
+}
+
+/**
+ * Copy properties from the source object to the
+ * target object.
+ *
+ * @param  {*} `val`
+ * @param  {String} `key`
+ */
+
+function copy(val, key) {
+  if (key === '__proto__') {
+    return;
+  }
+
+  var obj = this[key];
+  if (isObject(val) && isObject(obj)) {
+    mixinDeep(obj, val);
+  } else {
+    this[key] = val;
+  }
+}
+
+/**
+ * Returns true if `val` is an object or function.
+ *
+ * @param  {any} val
+ * @return {Boolean}
+ */
+
+function isObject(val) {
+  return isExtendable(val) && !Array.isArray(val);
+}
+
+/**
+ * Expose `mixinDeep`
+ */
+
+module.exports = mixinDeep;