add new functionality

1) Enable dynamic keys by evaluating any key starting with "$."
2) Enable arrays to be merged to one object

lib/jsonpath-object-transform.js

@@ -33,7 +33,11 @@
    */
   function walk(data, path, result, key) {
     var fn;
-
+    // if the key starts with $., assume that it's dynamic and should be evaluated
+    if (key && key.toString().indexOf('$.')>-1) {
+      key = jsonPath.eval(data, key);
+    }
+
     switch (type(path)) {
       case 'string':
         fn = seekSingle;
@@ -72,13 +76,9 @@
    * @param {string} key
    */
   function seekSingle(data, pathStr, result, key) {
-    if(pathStr.indexOf('$') < 0){
-      result[key] = pathStr;
-    }else{
-      var seek = jsonPath.eval(data, pathStr) || [];
+    var seek = jsonPath.eval(data, pathStr) || [];
 
-      result[key] = seek.length ? seek[0] : undefined;
-    }
+    result[key] = seek.length ? seek[0] : undefined;
   }
 
   /**
@@ -95,11 +95,16 @@
     var seek = jsonPath.eval(data, path) || [];
 
     if (seek.length && subpath) {
-      result = result[key] = [];
-
+      result[key] = [];
       seek[0].forEach(function(item, index) {
-        walk(item, subpath, result, index);
+        walk(item, subpath, result[key], index);
       });
+      if(pathArr[2] && pathArr[2].merge) {
+        // merge the individual objects in the array into one big object if the merge option is set to true
+        result[key] = result[key].reduce((reduced, el) => {
+          return Object.assign(reduced, el);
+        }, {});
+      }
     } else {
       result[key] = seek;
     }
@@ -130,10 +135,21 @@
    * @returns {object}
    */
   return function(data, path) {
-    var result = {};
-
+    var result = {},
+        needsWrapper = Array.isArray(data) && Array.isArray(path);
+    // wrap the data and path in a temp variable that will serve as the key for our initial iteration
+    // this is to resolve the fact that the code doesn't handle root level arrays natively
+    if (needsWrapper) {
+      data = { temp: data };
+      path = { temp: path };
+    }
+
     walk(data, path, result);
 
+    // unwrap the data before returning it
+    if (needsWrapper) {
+      result = result.temp;
+    }
     return result;
   };