functions: Add builtins functions to remove null or empty values

jmespath/functions.py

@@ -259,6 +259,34 @@ def _func_max(self, arg):
         else:
             return None
 
+    @signature({'types': ['object'], "variadic": True}, {'types': ['boolean']})
+    def _func_remove_null(self, obj, recursive):
+        if recursive:
+            return self._func_remove_recursive(obj, None)
+        else:
+            return self._func_remove(obj, None)
+
+    @signature({'types': ['object'], "variadic": True}, {'types': ['boolean']})
+    def _func_remove_empty(self, obj, recursive):
+        if recursive:
+            return self._func_remove_recursive(obj, None, '')
+        else:
+            return self._func_remove(obj, None, '')
+
+    def _func_remove(self, obj, *args):
+        return {k: v for k, v in obj.items() if not v in list(args)}
+
+    def _func_remove_recursive(self, obj, *args):
+        ret_dict = {}
+        for k in obj:
+            if not obj[k] in list(args):
+                ret_dict[k] = obj[k]
+
+            if isinstance(obj[k], dict):
+                ret_dict[k] = self._func_remove_recursive(obj[k], *args)
+
+        return ret_dict
+
     @signature({"types": ["object"], "variadic": True})
     def _func_merge(self, *arguments):
         merged = {}

tests/compliance/functions.json

@@ -12,9 +12,38 @@
     "empty_list": [],
     "empty_hash": {},
     "objects": {"foo": "bar", "bar": "baz"},
+    "objectsNull": {"foo": "bar", "bar": null},
+    "objectsEmpty": {"foo": "", "bar": null, "baz": "baz"},
+    "objectsEmptyNested": {"foo": "", "bar": null, "baz": {"foo": "", "bar": "bar", "foe": null}},
+    "objectsNullNested": {"foo": "bar", "bar": null, "baz": { "bar": null, "foo": "foo"}},
     "null_key": null
   },
   "cases": [
+    {
+      "expression": "remove_empty(objectsEmptyNested, `false`)",
+      "result": {"baz": {"foo": "", "bar": "bar", "foe": null}}
+    },
+
+    {
+      "expression": "remove_empty(objectsEmptyNested, `true`)",
+      "result": {"baz": {"bar": "bar"}}
+    },
+    {
+      "expression": "remove_empty(objectsEmpty, `false`)",
+      "result": {"baz": "baz"}
+    },
+    {
+      "expression": "remove_null(objectsNull, `false`)",
+      "result":  {"foo": "bar"}
+    },
+    {
+      "expression": "remove_null(objectsNullNested, `false`)",
+      "result": {"foo": "bar", "baz": { "bar": null, "foo": "foo"}}
+    },
+    {
+      "expression": "remove_null(objectsNullNested, `true`)",
+      "result": {"foo": "bar", "baz": {"foo": "foo"}}
+    },
     {
       "expression": "abs(foo)",
       "result": 1
@@ -189,7 +218,7 @@
     },
     {
       "expression": "length(@)",
-      "result": 12
+      "result": 16
     },
     {
       "expression": "length(strings[0])",