Merge pull request #7 from blackary/on-change

Add on_change keyword

setup.py

@@ -7,7 +7,7 @@
 
 setuptools.setup(
     name="streamlit-keyup",
-    version="0.1.7",
+    version="0.1.8",
     author="Zachary Blackwood",
     author_email="[email protected]",
     description="Text input that renders on keyup",

src/st_keyup/__init__.py

@@ -1,5 +1,5 @@
 from pathlib import Path
-from typing import Optional
+from typing import Any, Callable, Dict, Optional, Tuple
 
 import streamlit as st
 import streamlit.components.v1 as components
@@ -13,6 +13,9 @@ def st_keyup(
     value: str = "",
     key: Optional[str] = None,
     debounce: int = 0,
+    on_change: Optional[Callable] = None,
+    args: Optional[Tuple[Any, ...]] = None,
+    kwargs: Optional[Dict[str, Any]] = None,
 ):
     """
     Generate a text input that renders on keyup, debouncing the input by the
@@ -23,7 +26,16 @@ def st_keyup(
     when the user is typing. Since the input updating will cause the app to rerun,
     if you are having performance issues, you should consider setting a debounce
     value.
+
+    on_change is a callback function that will be called when the value changes.
+
+    args and kwargs are optional arguments which are passed to the on_change callback
+    function
     """
+
+    if key is None:
+        key = "st_keyup_" + label
+
     component_value = _component_func(
         label=label,
         value=value,
@@ -32,10 +44,26 @@ def st_keyup(
         default=value,
     )
 
+    if on_change is not None:
+        if "__previous_values__" not in st.session_state:
+            st.session_state["__previous_values__"] = {}
+
+        if component_value != st.session_state["__previous_values__"].get(key, value):
+            st.session_state["__previous_values__"][key] = component_value
+
+            if on_change:
+                if args is None:
+                    args = ()
+                if kwargs is None:
+                    kwargs = {}
+                on_change(*args, **kwargs)
+
     return component_value
 
 
 def main():
+    from datetime import datetime
+
     st.write("## Default keyup input")
     value = st_keyup("Enter a value")
 
@@ -47,15 +75,34 @@ def main():
     st.write(value)
 
     "## Keyup input with 500 millesecond debounce"
-    value = st_keyup("Enter a second value", debounce=500)
+    value = st_keyup("Enter a second value debounced", debounce=500)
 
     st.write(value)
 
+    def on_change():
+        st.write("Value changed!", datetime.now())
+
+    def on_change2(*args, **kwargs):
+        st.write("Value changed!", args, kwargs)
+
+    "## Keyup input with on_change callback"
+    value = st_keyup("Enter a third value", on_change=on_change)
+
+    "## Keyup input with on_change callback and debounce"
+    value = st_keyup("Enter a third value...", on_change=on_change, debounce=1000)
+    st.write(value)
+
+    "## Keyup input with args"
+    value = st_keyup("Enter a fourth value...", on_change=on_change2, args=("Hello", "World"), kwargs={"foo": "bar"})
+    st.write(value)
+
     "## Standard text input for comparison"
     value = st.text_input("Enter a value")
 
     st.write(value)
 
+    st.write(st.session_state)
+
 
 if __name__ == "__main__":
     main()