Select component: add prop multiple

chartlets.js/CHANGES.md

@@ -1,3 +1,9 @@
+## Version 0.1.5 (in development)
+
+* Add `multiple` property for `Select` component to enable the selection
+  of multiple elements. The `default` mode is supported at the moment.
+
+
 ## Version 0.1.4 (from 2025/03/06)
 
 * In `chartlets.js` we no longer emit warnings and errors in common 

chartlets.js/packages/lib/src/plugins/mui/Select.test.tsx

@@ -105,6 +105,43 @@ describe("Select", () => {
     });
   });
 
+  it("should fire 'value' property with an array of multiple values", () => {
+    const { recordedEvents, onChange } = createChangeHandler();
+    render(
+      <Select
+        id="sel"
+        type={"Select"}
+        label={"Colors"}
+        options={[10, 11, 12]}
+        value={[]}
+        onChange={onChange}
+        multiple={true}
+      />,
+    );
+    // open the Select component's list box
+    // note, we must use "mouseDown" as "click" doesn't work
+    fireEvent.mouseDown(screen.getByRole("combobox"));
+    // click item in the Select component's list box
+    const listBox = within(screen.getByRole("listbox"));
+    fireEvent.click(listBox.getByText(/11/i));
+    fireEvent.click(listBox.getByText(/12/i));
+    expect(recordedEvents.length).toBe(2);
+    expect(recordedEvents).toEqual([
+      {
+        componentType: "Select",
+        id: "sel",
+        property: "value",
+        value: [11],
+      },
+      {
+        componentType: "Select",
+        id: "sel",
+        property: "value",
+        value: [12],
+      },
+    ]);
+  });
+
   it("should fire 'value' property with object options", () => {
     const { recordedEvents, onChange } = createChangeHandler();
     render(

chartlets.js/packages/lib/src/plugins/mui/Select.tsx

@@ -16,6 +16,7 @@ export type SelectOption =
 
 interface SelectState extends ComponentState {
   options?: SelectOption[];
+  multiple?: boolean;
 }
 
 interface SelectProps extends ComponentProps, SelectState {}
@@ -30,14 +31,19 @@ export function Select({
   style,
   tooltip,
   label,
+  multiple = false,
   onChange,
 }: SelectProps) {
-  const handleChange = (event: SelectChangeEvent) => {
+  const handleChange = (event: SelectChangeEvent<unknown>) => {
     if (id) {
-      let newValue: string | number = event.target.value;
-      if (typeof value == "number") {
-        newValue = Number.parseInt(newValue);
+      let newValue: string | number | (string | number)[] = multiple
+        ? (event.target.value as (string | number)[])
+        : (event.target.value as string | number);
+
+      if (!multiple && typeof value === "number") {
+        newValue = Number.parseInt(newValue as string);
       }
+
       onChange({
         componentType: type,
         id: id,
@@ -54,24 +60,26 @@ export function Select({
           labelId={`${id}-label`}
           id={id}
           name={name}
-          value={`${value}`}
+          value={value}
           disabled={disabled}
-          onChange={handleChange}
-        >
+          multiple={multiple}
+          onChange={handleChange}>
           {Array.isArray(options) &&
-            options.map(normalizeSelectOption).map(([value, text], index) => (
-              <MuiMenuItem key={index} value={value}>
-                {text}
-              </MuiMenuItem>
-            ))}
+            options
+              .map(normalizeSelectOption)
+              .map(([optionValue, optionLabel], index) => (
+                <MuiMenuItem key={index} value={optionValue}>
+                  {optionLabel}
+                </MuiMenuItem>
+              ))}
         </MuiSelect>
       </MuiFormControl>
     </Tooltip>
   );
 }
 
 function normalizeSelectOption(
-  option: SelectOption,
+  option: SelectOption
 ): [string | number, string] {
   if (isString(option)) {
     return [option, option];

chartlets.py/CHANGES.md

@@ -1,3 +1,9 @@
+## Version 0.1.5 (in development)
+
+* Add `multiple` property for `Select` component to enable the
+  of multiple elements.
+
+
 ## Version 0.1.4 (from 2025/03/06)
 
 * New (MUI) components
@@ -39,6 +45,7 @@
   - `Switch`
   - `Slider`
   - `Tabs` and `Tab`
+
 
 ## Version 0.0.29 (from 2024/11/26)
 

chartlets.py/chartlets/component.py

@@ -19,7 +19,7 @@ class Component(ABC):
     name: str | None = None
     """HTML `name` attribute. Optional."""
 
-    value: bool | int | float | str | None = None
+    value: bool | int | float | str | list[bool | int | float | str] | None = None
     """HTML `value` attribute. Required for specific components."""
 
     style: dict[str, Any] | None = None

chartlets.py/chartlets/components/select.py

@@ -13,6 +13,11 @@ class Select(Component):
     """Select components are used for collecting user provided
     information from a list of options."""
 
+    multiple: bool | None = None
+    """Allows for multiple selection in Select Menu. If `true`, value 
+    must be an array.
+    """
+
     options: list[SelectOption] = field(default_factory=list)
     """The options given as a list of number or text values or a list
     of (value, label) pairs.

chartlets.py/demo/my_extension/__init__.py

@@ -5,6 +5,8 @@
 from .my_panel_4 import panel as my_panel_4
 from .my_panel_5 import panel as my_panel_5
 from .my_panel_6 import panel as my_panel_6
+from .my_panel_7 import panel as my_panel_7
+
 
 ext = Extension(__name__)
 ext.add(my_panel_1)
@@ -13,3 +15,4 @@
 ext.add(my_panel_4)
 ext.add(my_panel_5)
 ext.add(my_panel_6)
+ext.add(my_panel_7)

chartlets.py/demo/my_extension/my_panel_7.py

@@ -0,0 +1,93 @@
+import altair as alt
+import pandas as pd
+from chartlets import Component, Input, State, Output
+from chartlets.components import VegaChart, Box, Select, Typography
+
+from server.context import Context
+from server.panel import Panel
+
+
+panel = Panel(__name__, title="Panel G")
+
+
+@panel.layout(State("@app", "selectedDatasetId"))
+def render_panel(
+    ctx: Context,
+    selected_dataset_id: str = "",
+) -> Component:
+    dataset = ctx.datasets.get(selected_dataset_id)
+    variable_names, selected_var_names = get_variable_names(dataset)
+
+    select = Select(
+        id="selected_variable_name",
+        value=[],
+        label="Variable",
+        options=[(v, v) for v in variable_names],
+        style={"flexGrow": 0, "minWidth": 120},
+        multiple=True,
+        tooltip="Select the variables of the test dataset",
+    )
+    control_group = Box(
+        style={
+            "display": "flex",
+            "flexDirection": "row",
+            "padding": 4,
+            "justifyContent": "center",
+            "gap": 4,
+        },
+        children=[select],
+    )
+
+    text = update_info_text(ctx, selected_dataset_id)
+    info_text = Typography(id="info_text", children=text)
+
+    return Box(
+        style={
+            "display": "flex",
+            "flexDirection": "column",
+            "width": "100%",
+            "height": "100%",
+        },
+        children=[info_text, control_group],
+    )
+
+
+def get_variable_names(
+    dataset: pd.DataFrame,
+    prev_var_name: str | None = None,
+) -> tuple[list[str], list[str]]:
+    """Get the variable names and the selected variable name
+    for the given dataset and previously selected variable name.
+    """
+
+    if dataset is not None:
+        var_names = [v for v in dataset.keys() if v != "x"]
+    else:
+        var_names = []
+
+    if prev_var_name and prev_var_name in var_names:
+        var_name = prev_var_name
+    elif var_names:
+        var_name = var_names[0]
+    else:
+        var_name = ""
+
+    return var_names, var_name
+
+
+@panel.callback(
+    Input("@app", "selectedDatasetId"),
+    Input("selected_variable_name", "value"),
+    Output("info_text", "children"),
+)
+def update_info_text(
+    ctx: Context,
+    dataset_id: str = "",
+    selected_var_names: list[str] | None = None,
+) -> list[str]:
+
+    if selected_var_names is not None:
+        text = ", ".join(map(str, selected_var_names))
+        return [f"The dataset is {dataset_id} and the selected variables are: {text}"]
+    else:
+        return [f"The dataset is {dataset_id} and no variables are selected."]