Added triggered_id to clientside callbacks

Author: AnnMarieW

dash/dash-renderer/src/actions/callbacks.ts

@@ -262,6 +262,9 @@ async function handleClientside(
             prop_id: prop_id,
             value: inputDict[prop_id]
         }));
+        dc.callback_context.triggered_id = getTriggeredId(
+            payload.changedPropIds
+        );
         dc.callback_context.inputs_list = inputs;
         dc.callback_context.inputs = inputDict;
         dc.callback_context.states_list = state;
@@ -576,6 +579,16 @@ function inputsToDict(inputs_list: any) {
     return inputs;
 }
 
+function getTriggeredId(triggered: string[]): string | object {
+    // for regular callbacks,  takes the first triggered prop_id, e.g.  "btn.n_clicks" and returns "btn"
+    // for pattern matching callback, e.g. '{"index":0, "type":"btn"}' and returns {index:0, type: "btn"}'
+    let componentId = triggered[0].split('.')[0];
+    if (componentId.startsWith('{')) {
+        componentId = JSON.parse(componentId);
+    }
+    return componentId;
+}
+
 export function executeCallback(
     cb: IPrioritizedCallback,
     config: any,

tests/integration/clientside/assets/clientside.js

@@ -63,6 +63,12 @@ window.dash_clientside.clientside = {
         return triggered.map(t => `${t.prop_id} = ${t.value}`).join(', ');
     },
 
+    triggered_id_to_str: function(n_clicks0, n_clicks1) {
+        const triggered = dash_clientside.callback_context.triggered_id;
+        const triggered_id = typeof triggered === "string" ? triggered : triggered.btn1
+        return triggered_id
+    },
+
     inputs_to_str: function(n_clicks0, n_clicks1) {
         const inputs = dash_clientside.callback_context.inputs;
         const keys = Object.keys(inputs);

tests/integration/clientside/test_clientside.py

@@ -829,3 +829,45 @@ def test_clsd019_clientside_inline_promise(dash_duo):
 
     dash_duo.start_server(app)
     dash_duo.wait_for_text_to_equal("#output-div", "initial-inline")
+
+
+def test_clsd020_clientside_callback_context_triggered_id(dash_duo):
+    app = Dash(__name__, assets_folder="assets")
+
+    app.layout = html.Div(
+        [
+            html.Button("btn0", id="btn0"),
+            html.Button("btn1:0", id={"btn1": 0}),
+            html.Button("btn1:1", id={"btn1": 1}),
+            html.Button("btn1:2", id={"btn1": 2}),
+            html.Div(id="output-clientside", style={"font-family": "monospace"}),
+        ]
+    )
+
+    app.clientside_callback(
+        ClientsideFunction(namespace="clientside", function_name="triggered_id_to_str"),
+        Output("output-clientside", "children"),
+        [Input("btn0", "n_clicks"), Input({"btn1": ALL}, "n_clicks")],
+    )
+
+    dash_duo.start_server(app)
+
+    dash_duo.wait_for_text_to_equal("#output-clientside", "")
+
+    dash_duo.find_element("#btn0").click()
+
+    dash_duo.wait_for_text_to_equal(
+        "#output-clientside",
+        "btn0",
+    )
+
+    dash_duo.find_element("button[id*='btn1\":0']").click()
+
+    dash_duo.wait_for_text_to_equal("#output-clientside", '0')
+
+    dash_duo.find_element("button[id*='btn1\":2']").click()
+
+    dash_duo.wait_for_text_to_equal(
+        "#output-clientside",
+        '2'
+    )