chore: import upstream snapshot with attribution

haystack/components/joiners/string_joiner.py

@@ -0,0 +1,56 @@
+# SPDX-FileCopyrightText: 2022-present deepset GmbH <info@deepset.ai>
+#
+# SPDX-License-Identifier: Apache-2.0
+
+
+from haystack import component
+from haystack.core.component.types import Variadic
+
+
+@component
+class StringJoiner:
+    """
+    Component to join strings from different components to a list of strings.
+
+    ### Usage example
+
+    ```python
+    from haystack.components.joiners import StringJoiner
+    from haystack.components.builders import PromptBuilder
+    from haystack.core.pipeline import Pipeline
+
+    from haystack.components.generators.chat import OpenAIChatGenerator
+    from haystack.dataclasses import ChatMessage
+
+    string_1 = "What's Natural Language Processing?"
+    string_2 = "What is life?"
+
+    pipeline = Pipeline()
+    pipeline.add_component("prompt_builder_1", PromptBuilder("Builder 1: {{query}}"))
+    pipeline.add_component("prompt_builder_2", PromptBuilder("Builder 2: {{query}}"))
+    pipeline.add_component("string_joiner", StringJoiner())
+
+    pipeline.connect("prompt_builder_1.prompt", "string_joiner.strings")
+    pipeline.connect("prompt_builder_2.prompt", "string_joiner.strings")
+
+    print(pipeline.run(data={"prompt_builder_1": {"query": string_1}, "prompt_builder_2": {"query": string_2}}))
+
+    # >> {"string_joiner": {"strings": ["Builder 1: What's Natural Language Processing?", "Builder 2: What is life?"]}}
+    ```
+    """
+
+    @component.output_types(strings=list[str])
+    def run(self, strings: Variadic[str]) -> dict[str, list[str]]:
+        """
+        Joins strings into a list of strings
+
+        :param strings:
+            strings from different components
+
+        :returns:
+            A dictionary with the following keys:
+            - `strings`: Merged list of strings
+        """
+
+        out_strings = list(strings)
+        return {"strings": out_strings}