map_contains

src/ytdl_sub/script/functions/map_functions.py

@@ -2,6 +2,7 @@ from typing import Optional
 
 from ytdl_sub.script.types.map import Map
 from ytdl_sub.script.types.resolvable import AnyArgument
+from ytdl_sub.script.types.resolvable import Boolean
 from ytdl_sub.script.types.resolvable import Hashable
 from ytdl_sub.script.utils.exceptions import KeyDoesNotExistRuntimeException
 
@@ -21,3 +22,10 @@ class MapFunctions:
                 f"Tried to call %map_get with key {key.value}, but it does not exist"
             )
         return mapping.value[key]
+
+    @staticmethod
+    def map_contains(mapping: Map, key: Hashable) -> Boolean:
+        """
+        Returns True if the key is in the Map. False otherwise.
+        """
+        return Boolean(key in mapping.value)

tests/unit/script/functions/test_map_functions.py

@@ -46,3 +46,25 @@ class TestMapFunctions:
                     "output": "{%map_get(input_map, 'dne')}",
                 }
             ).resolve()
+
+    @pytest.mark.parametrize(
+        "contains_value, expected_value",
+        [
+            ("'key'", True),
+            ("'dne'", False),
+            ("%string(%array_at(['dne', 'key'], 1))", True),
+        ],
+    )
+    def test_map_contains(self, contains_value: str, expected_value: bool):
+        output = (
+            Script(
+                {
+                    "input_map": "{{'key': 'value'}}",
+                    "output": f"{{%map_contains(input_map, {contains_value})}}",
+                }
+            )
+            .resolve(update=True)
+            .get("output")
+            .native
+        )
+        assert output == expected_value