chore(docs): update readme

README_AGGREGATIONS.md

@@ -141,7 +141,7 @@ Returns **[Object][2]** an object containing a MongoDb projection object
     *   `$0.from`  
     *   `$0.as`  
     *   `$0.localField`  
-    *   `$0.foreignField`  
+    *   `$0.foreignField`   (optional, default `'id'`)
     *   `$0.pipeline`   (optional, default `[]`)
 
 ### Properties
@@ -161,11 +161,116 @@ Returns **[Object][2]** an object containing a MongoDb projection object
     *   `options.from`  
     *   `options.as`  
     *   `options.localField`  
-    *   `options.foreignField`  
+    *   `options.foreignField`   (optional, default `'id'`)
     *   `options.pipeline`   (optional, default `[]`)
 
 Returns **[Object][2]** 
 
+## REDUCE
+
+### Parameters
+
+*   `$0` **[Object][2]** 
+
+    *   `$0.input`  
+    *   `$0.initialValue`   (optional, default `{}`)
+    *   `$0.inExpression`  
+
+### Properties
+
+*   `input` **[String][1]** any expression resolving to an array
+*   `initialValue` **any** the initial value used for reduction
+*   `inExpression` **[Object][2]** any expression applied to each element of the array
+
+## REDUCE
+
+### Parameters
+
+*   `options` **ReduceOptions** 
+
+    *   `options.input`  
+    *   `options.initialValue`   (optional, default `{}`)
+    *   `options.inExpression`  
+
+Returns **[Object][2]** 
+
+## APPEND\_OBJECTS
+
+Returns a $mergeObjects expression that appends the result of the given expressions to $$value
+
+### Parameters
+
+*   `expressions` **...any** a list of expressions that evaluate to an object
+
+Returns **[Object][2]** 
+
+## LET
+
+### Parameters
+
+*   `$0` **[Object][2]** 
+
+    *   `$0.vars`  
+    *   `$0.inExpression`  
+
+### Properties
+
+*   `vars` **[Object][2]** an object defining additional variables for the expression
+*   `inExpression` **[Object][2]** any expression
+
+## LET
+
+### Parameters
+
+*   `options` **LetOptions** 
+
+    *   `options.vars`  
+    *   `options.inExpression`  
+
+## TO\_OBJECT
+
+### Parameters
+
+*   `$0` **[Object][2]** 
+
+    *   `$0.key`   (optional, default `"$$this"`)
+    *   `$0.value`  
+
+### Properties
+
+*   `key` **[String][1]** the object key
+*   `expression` **[Object][2]** any expression
+
+## TO\_OBJECT
+
+### Parameters
+
+*   `options` **ToObjectOptions** 
+
+    *   `options.key`   (optional, default `"$$this"`)
+    *   `options.value`  
+
+## CONCAT\_STRINGS
+
+### Parameters
+
+*   `strings` **...any** strings to concat
+
+Returns **[Object][2]** 
+
+## JOIN\_STRINGS
+
+### Parameters
+
+*   `separator` **[String][1]** separator to be used for joining given strings
+*   `strings` **...any** strings to concat
+
+Returns **[Object][2]** 
+
+## CONCAT\_ARRAYS
+
+Returns **[Object][2]** 
+
 ## ELEMENT\_AT
 
 ### Parameters

README_SIMPLE_RESOURCE_STORAGE.md

@@ -54,17 +54,17 @@ Returns **[Array][4]<[Object][5]>**&#x20;
 
 Returns all children of a certain type/collection. Imagine this method walking a tree and returning all leaves at a certain level.
 
-Example:
-
 ### Parameters
 
 *   `resourceIds` **([String][1] | [Array][4]<[String][1]>)** resource ids that will added to the resource path i.e. /users/${id}/documents/${id}
 *   `childPath` **([String][1] | [Array][4]<[String][1]>)** the path of the children to query e.g. /api\_clients/queues/messages
 *   `options` **GetOptions**&#x20;
 
+Returns **[Promise][6]\<ChildrenAndResourcePaths>**&#x20;
+
 ## find
 
-*   **See**: [README\_AGGREGATIONS.md][6]
+*   **See**: [README\_AGGREGATIONS.md][7]
 
 Returns all resources that pass the given aggregation stages.
 
@@ -82,7 +82,7 @@ Returns true if a resource with given ids exists.
 
 *   `resourceIds` **([String][1] | [Array][4]<[String][1]>)**&#x20;
 
-Returns **[boolean][7]**&#x20;
+Returns **[boolean][8]**&#x20;
 
 ## create
 
@@ -126,6 +126,8 @@ Returns **void**&#x20;
 
 [5]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object
 
-[6]: README_AGGREGATIONS.md
+[6]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Promise
+
+[7]: README_AGGREGATIONS.md
 
-[7]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean
+[8]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean