add ability to write nested array

README.md

@@ -377,6 +377,142 @@ The expected output.
 ]
 ```
 
+### Nested Array Handling
+
+Suppose this is the data
+
+```javascript
+var data = {
+    "name": "Sarvpriy",
+    "users": [
+      {
+        id: "1",
+        name: "arya",
+        comments: [
+          { 
+            text: "user id 1 comment no 1",
+            replies: [{
+                title: "reply 1 to user id 1 comment no 1"
+            }, {
+                title: "reply 2 to user id 1 comment no 1"
+            }]
+          },
+          { 
+            text: "user id 1 comment no 2",
+            replies: [{
+                title: "reply 1 to user id 1 comment no 2"
+            }, {
+                title: "reply 2 to user id 1 comment no 2"
+            }]
+          }
+        ]
+      }, {
+        id: "2",
+        name: "john",
+        comments: [
+          { 
+            text: "user id 2 comment no 1",
+            replies: [{
+                title: "reply 1 to user id 2 comment no 1"
+            }, {
+                title: "reply 2 to user id 2 comment no 1"
+            }]
+          },
+          { 
+            text: "user id 2 comment no 2",
+            replies: [{
+                title: "reply 1 to user id 2 comment no 2"
+            }, {
+                title: "reply 2 to user id 2 comment no 2"
+            }]
+          }
+        ]
+      }
+    ]
+};
+```
+
+and you want this type of result
+```javascript
+{
+	"myname":"Sarvpriy",
+	"myusers": [{
+		"userid":"1",
+		"comments": [{
+			"mytext":"user id 1's comment no 1",
+			"myreplies": [{
+				"mytitle":"reply 1 to user id 1's comment no 1"
+			},{
+				"mytitle":"reply 2 to user id 1's comment no 1"
+			}]
+		},{
+			"mytext":"user id 1's comment no 2",
+			"myreplies": [{
+				"mytitle":"reply 1 to user id 1's comment no 2"
+			},{
+				"mytitle":"reply 2 to user id 1's comment no 2"
+			}]
+		}]
+	},{
+		"userid":"2",
+		"comments": [{
+			"mytext":"user id 2's comment no 1",
+			"myreplies": [{
+				"mytitle":"reply 1 to user id 2's comment no 1"
+			},{
+				"mytitle":"reply 2 to user id 2's comment no 1"
+			}]
+		},{
+			"mytext":"user id 2's comment no 2",
+			"myreplies": [{
+				"mytitle":"reply 1 to user id 2's comment no 2"
+			},{
+				"mytitle":"reply 2 to user id 2's comment no 2"
+			}]
+		}]
+	}]
+}
+```
+This can be achieved through the `operate` params. 
+But there are two problems
+- You cannot save your map object in other places ex. in Database.
+- `operate` doesn't work on the nested level(more then one level deep).
+
+no need to say that it is extreamly complex.
+To acheive this the `map` object will look like this
+
+```javascript
+var map = {
+  "item" : {
+    "myname": "name",
+    "myusers[users]": {
+        "userid": "id",
+        "comments[comments]": {
+            "mytext": "text",
+            "myreplies[replies]": {
+                "mytitle": "title"
+            }
+        }
+    }
+  }
+};
+```
+So in a nutshel the `map` object should be
+
+```javascript
+var map = {
+  "item": {
+    "new_arr_key[array_key_in_data]": {    // `map` object b/w elements inside the new_arr_key and array_key_in_data
+      "some_new_key": "key_from_an_elem_in_array_key_in_data"
+      "nested_key[nested_key_inside_an_elem_in_array_key_in_data]": { // again `map` object
+        .
+        ... // nesting goes on and on
+      }
+    }
+  }
+}
+```
+
 Enjoy!
 
 ## Changelog

index.js

@@ -3,6 +3,9 @@
 var _ = require('lodash');
 
 var DataTransform = function(data, map){
+	if (_.hasIn(map, 'item') && _.isObject(map.item)) {
+		map.item = updateArrayKeys(map.item, data)
+	}
 
 	return {
 
@@ -171,6 +174,79 @@ var DataTransform = function(data, map){
 
 };
 
+const getSrcKey = function (newkey) {
+    if (newkey.indexOf('[') !== -1 && newkey.endsWith(']') ) {
+        return [
+        	newkey.substring(0, newkey.indexOf('[')),
+        	newkey.substring(newkey.indexOf('[') + 1, newkey.length - 1)
+        ]
+    }
+    throw `SyntaxError: no source key found`
+};
+
+function updateArrayKeys(map, data) {
+	let newmap = {}
+
+	// loop thru map object
+	for(let [newkey, oldkey] of _.entries(map)) {
+
+		// find keys ending with ]
+		if (_.endsWith(newkey, ']')) {
+
+			// extract srckey, make newkey
+			var [ tempkey, srckey ] = getSrcKey(newkey)
+			newmap[tempkey] = map[newkey]
+
+			// start creating newoldkeys array
+			var newoldkey = []
+
+			// find length of srckey
+			_.get(data, srckey).forEach((elem, index) => {
+				var obj = {}
+
+				// loop thru the oldkey
+				for(let [oldkey_key, oldkey_val] of _.entries(oldkey)) {
+
+					// if any key ends with ] 
+					if (_.endsWith(oldkey_key, ']')) {
+
+						// then prepend srckey with index after [
+						const newoldkey_key = `${oldkey_key.slice(0, oldkey_key.indexOf('[') + 1)}${srckey}[${index}].${oldkey_key.slice(oldkey_key.indexOf('[') + 1)}`
+						for (const [k, v] of _.entries(updateArrayKeys({ [newoldkey_key]: oldkey_val }, data))) {
+							obj[k] = v
+						}
+					}
+
+					// if val is string then prepend srckey with index
+					if (_.isString(oldkey_val)) {
+						obj[oldkey_key] = `${srckey}[${index}].${oldkey_val}`
+					}
+					// else leave
+				}
+
+				// push to newoldkey array
+				newoldkey.push(obj)
+			})
+
+			newmap[tempkey] = newoldkey
+
+		} 
+		else if(_.isObject(oldkey) && !_.isArray(oldkey)) {
+			newmap[newkey] = updateArrayKeys(oldkey, data)
+		} 
+		else if(_.isArray(oldkey)) {
+			newmap[newkey] = _.map(oldkey, (val) => {
+				if(_.isString(val)) return val
+				else if(_.isObject(val) && !_.isArray(val)) return updateArrayKeys(val, data)
+			})
+		} 
+		else {
+			newmap[newkey] = oldkey
+		}
+	}
+	return newmap
+}
+
 exports.DataTransform = DataTransform;
 
 exports.transform = function(data, map, context) {

test/nestedArraySpec.js

@@ -0,0 +1,149 @@
+var DataTransform = require('../index.js').DataTransform,
+	transform = require('../index.js').transform,
+	_ = require("lodash");
+
+var test1_data = {
+    "name": "Sarvpriy",
+    "users": [
+      {
+        id: "1",
+        name: "arya",
+        comments: [
+          { 
+            text: "user id 1 comment no 1",
+            replies: [{
+                title: "reply 1 to user id 1 comment no 1"
+            }, {
+                title: "reply 2 to user id 1 comment no 1"
+            }]
+          },
+          { 
+            text: "user id 1 comment no 2",
+            replies: [{
+                title: "reply 1 to user id 1 comment no 2"
+            }, {
+                title: "reply 2 to user id 1 comment no 2"
+            }]
+          }
+        ]
+      }, {
+        id: "2",
+        name: "john",
+        comments: [
+          { 
+            text: "user id 2 comment no 1",
+            replies: [{
+                title: "reply 1 to user id 2 comment no 1"
+            }, {
+                title: "reply 2 to user id 2 comment no 1"
+            }]
+          },
+          { 
+            text: "user id 2 comment no 2",
+            replies: [{
+                title: "reply 1 to user id 2 comment no 2"
+            }, {
+                title: "reply 2 to user id 2 comment no 2"
+            }]
+          }
+        ]
+      }
+    ]
+};
+
+var test1_map = {
+    "item" : {
+      "myname": "name",
+      "myusers[users]": {
+          "userid": "id",
+          "comments[comments]": {
+              "mytext": "text",
+              "myreplies[replies]": {
+                  "mytitle": "title"
+              }
+          }
+      }
+    }
+  };
+
+var test1_expected = {
+	"myname":"Sarvpriy",
+	"myusers": [{
+		"userid":"1",
+		"comments": [{
+			"mytext":"user id 1 comment no 1",
+			"myreplies": [{
+				"mytitle":"reply 1 to user id 1 comment no 1"
+			},{
+				"mytitle":"reply 2 to user id 1 comment no 1"
+			}]
+		},{
+			"mytext":"user id 1 comment no 2",
+			"myreplies": [{
+				"mytitle":"reply 1 to user id 1 comment no 2"
+			},{
+				"mytitle":"reply 2 to user id 1 comment no 2"
+			}]
+		}]
+	},{
+		"userid":"2",
+		"comments": [{
+			"mytext":"user id 2 comment no 1",
+			"myreplies": [{
+				"mytitle":"reply 1 to user id 2 comment no 1"
+			},{
+				"mytitle":"reply 2 to user id 2 comment no 1"
+			}]
+		},{
+			"mytext":"user id 2 comment no 2",
+			"myreplies": [{
+				"mytitle":"reply 1 to user id 2 comment no 2"
+			},{
+				"mytitle":"reply 2 to user id 2 comment no 2"
+			}]
+		}]
+	}]
+};
+
+describe("node-json-transform", function() {
+
+	it("should change array keys and prefix the oldkeys with full srckey path", function() {
+		expect(transform(test1_data, test1_map)).toEqual(test1_expected);
+	});
+
+});
+
+
+var test2_data = {
+    "to": [{
+        "email": "sarvpriy.arya@gmail.com",
+        "name": "Sarvpriy Arya"
+    },{
+        "email": "sarvpriy.arya@gmail.com",
+        "name": "Sarvpriy Arya"
+    }]
+};
+
+var test2_map = {
+  "item": {
+        "personalizations": [{
+            "to[to]": {
+                "email": "email"
+            }
+        }]
+    }
+};
+
+var test2_expected = {"personalizations":[{"to":[{"email":"sarvpriy.arya@gmail.com"},{"email":"sarvpriy.arya@gmail.com"}]}]}
+
+describe("node-json-transform", function() {
+
+  it("should work when top level is not an array", function() {
+    expect(transform(test2_data, test2_map)).toEqual(test2_expected);
+  });
+
+  it("should handle root object ex. { item: `payload`}", function() {
+    expect(transform({"payload": test2_data}, { "item": "payload"})).toEqual(test2_data);
+  });
+
+});