feat: add tests for list property

examples/src/components/DataBindingTests.stories.tsx

@@ -2,7 +2,7 @@ import React, { useEffect } from 'react';
 import type { Meta, StoryObj } from '@storybook/react';
 import { within, expect, waitFor, userEvent } from '@storybook/test';
 
-import { StringPropertyTest, NumberPropertyTest, BooleanPropertyTest, ColorPropertyTest, EnumPropertyTest, NestedViewModelTest, TriggerPropertyTest, PersonForm, PersonInstances, ImagePropertyTest } from './DataBindingTests';
+import { StringPropertyTest, NumberPropertyTest, BooleanPropertyTest, ColorPropertyTest, EnumPropertyTest, NestedViewModelTest, TriggerPropertyTest, PersonForm, PersonInstances, ImagePropertyTest, TodoListTest } from './DataBindingTests';
 
 const meta: Meta = {
     title: 'Tests/DataBinding',
@@ -385,4 +385,100 @@ export const ImagePropertyStory: StoryObj = {
             expect(canvas.getByTestId('current-image-url')).toBeTruthy();
         }, { timeout: 5000 });
     }
+};
+
+
+export const TodoListStory: StoryObj = {
+    name: 'Todo List Property',
+    render: () => <TodoListTest src="db_list_test.riv" />,
+    play: async ({ canvasElement }) => {
+        const canvas = within(canvasElement);
+
+        // Wait for the Rive file to load
+        await waitFor(() => {
+            expect(canvas.getByTestId('list-length')).toBeTruthy();
+        }, { timeout: 3000 });
+
+        const initialLengthText = canvas.getByTestId('list-length').textContent;
+        const initialCount = parseInt(initialLengthText?.match(/Items: (\d+)/)?.[1] || '0');
+
+        // Test 1: addInstance - Add item to end
+        const addButton = canvas.getByTestId('add-item-button');
+        await userEvent.click(addButton);
+
+        await waitFor(() => {
+            expect(canvas.getByTestId('list-length').textContent).toContain(`Items: ${initialCount + 1}`);
+        });
+
+        // Test 2: addInstanceAt - Add item at specific index (if we have items)
+        if (initialCount > 0) {
+            const addAtButton = canvas.getByTestId('add-item-at-button');
+            await userEvent.click(addAtButton);
+
+            await waitFor(() => {
+                expect(canvas.getByTestId('list-length').textContent).toContain(`Items: ${initialCount + 2}`);
+            });
+        }
+
+        // Test 3: getInstanceAt - Interact with specific items
+        const currentCount = initialCount + (initialCount > 0 ? 2 : 1);
+        if (currentCount > 0) {
+            await waitFor(() => {
+                expect(canvas.getByTestId('todo-item-0')).toBeTruthy();
+            });
+
+            // Edit the first item
+            const todoText = canvas.getByTestId('todo-text-0');
+            await userEvent.clear(todoText);
+
+            // Wait for the input to be cleared to avoid issues with autocomplete
+            await waitFor(() => {
+                expect((todoText as HTMLInputElement).value).toBe('');
+            }, { timeout: 2000 });
+
+            await userEvent.click(todoText);
+            await userEvent.paste('Test Item');
+
+            await waitFor(() => {
+                expect(canvas.getByTestId('todo-text-value-0').textContent).toContain('Test Item');
+            }, { timeout: 3000 });
+
+        }
+
+        // Test 4: swap - Swap first two items
+        if (currentCount >= 2) {
+            const firstText = canvas.getByTestId<HTMLInputElement>('todo-text-0').value;
+            const secondText = canvas.getByTestId<HTMLInputElement>('todo-text-1').value;
+
+            const swapButton = canvas.getByTestId('swap-button');
+            await userEvent.click(swapButton);
+
+            await waitFor(() => {
+                expect(canvas.getByTestId('todo-text-0')).toHaveValue(secondText);
+                expect(canvas.getByTestId('todo-text-1')).toHaveValue(firstText);
+            }, { timeout: 3000 });
+        }
+
+        // Test 5: removeInstance - Remove by instance reference
+        if (currentCount > 0) {
+            const removeInstanceButton = canvas.getByTestId('remove-instance-button');
+            await userEvent.click(removeInstanceButton);
+
+            await waitFor(() => {
+                expect(canvas.getByTestId('list-length').textContent).toContain(`Items: ${currentCount - 1}`);
+            }, { timeout: 3000 });
+        }
+
+        // Test 6: removeInstanceAt - Remove by index
+        const afterRemoveInstance = currentCount > 0 ? currentCount - 1 : 0;
+        if (afterRemoveInstance > 0) {
+            const removeIndexButton = canvas.getByTestId('remove-index-button');
+            await userEvent.click(removeIndexButton);
+
+            await waitFor(() => {
+                expect(canvas.getByTestId('list-length').textContent).toContain(`Items: ${afterRemoveInstance - 1}`);
+            }, { timeout: 3000 });
+        }
+
+    }
 };

examples/src/components/DataBindingTests.tsx

@@ -11,7 +11,9 @@ import Rive, {
     useViewModelInstanceColor,
     useViewModelInstanceTrigger,
     useViewModelInstanceImage,
-    decodeImage
+    decodeImage,
+    ViewModelInstance,
+    useViewModelInstanceList
 } from '@rive-app/react-webgl2';
 
 
@@ -610,4 +612,178 @@ export const ImagePropertyTest = ({ src }: { src: string }) => {
             )}
         </div>
     );
+};
+
+// List Property Test
+
+const TodoItemComponent = ({
+    index,
+    todoItem
+}: {
+    index: number;
+    todoItem: ViewModelInstance | null;
+}) => {
+    const { value: text, setValue: setText } = useViewModelInstanceString('text', todoItem);
+    const { value: isDone, setValue: setIsDone } = useViewModelInstanceBoolean('isDone', todoItem);
+
+    if (!todoItem) {
+        return <div data-testid={`todo-item-${index}`}>Item not found</div>;
+    }
+
+    return (
+        <div data-testid={`todo-item-${index}`} style={{
+            display: 'flex',
+            alignItems: 'center',
+            gap: '10px',
+            padding: '8px',
+            border: '1px solid #ccc',
+            marginBottom: '4px'
+        }}>
+            <input
+                data-testid={`todo-checkbox-${index}`}
+                type="checkbox"
+                checked={isDone ?? false}
+                onChange={(e) => setIsDone(e.target.checked)}
+            />
+            <input
+                data-testid={`todo-text-${index}`}
+                type="text"
+                value={text || ''}
+                onChange={(e) => setText(e.target.value)}
+                style={{ flex: 1 }}
+            />
+            <div data-testid={`todo-text-value-${index}`} style={{ fontSize: '12px', color: '#666' }}>
+                Text: {text}
+            </div>
+            <div data-testid={`todo-done-value-${index}`} style={{ fontSize: '12px', color: '#666' }}>
+                Done: {isDone ? 'true' : 'false'}
+            </div>
+        </div>
+    );
+};
+
+export const TodoListTest = ({ src }: { src: string }) => {
+    const { rive, RiveComponent } = useRive({
+        src,
+        autoplay: true,
+        artboard: "Artboard",
+        autoBind: false,
+        stateMachines: "State Machine 1",
+    });
+
+    const viewModel = useViewModel(rive, { name: 'TodoList' });
+    const viewModelInstance = useViewModelInstance(viewModel, { rive });
+
+    const {
+        length,
+        addInstance,
+        addInstanceAt,
+        removeInstance,
+        removeInstanceAt,
+        getInstanceAt,
+        swap
+    } = useViewModelInstanceList('items', viewModelInstance);
+
+    const handleAddItem = () => {
+        const todoItemViewModel = rive?.viewModelByName?.('TodoItem');
+        if (todoItemViewModel) {
+            const newTodoItem = todoItemViewModel.instance?.();
+            if (newTodoItem) {
+                addInstance(newTodoItem);
+            }
+        }
+    };
+
+    const handleAddItemAt = () => {
+        const todoItemViewModel = rive?.viewModelByName?.('TodoItem');
+        if (todoItemViewModel && length > 0) {
+            const newTodoItem = todoItemViewModel.instance?.();
+            if (newTodoItem) {
+                addInstanceAt(newTodoItem, 1);
+            }
+        }
+    };
+
+    const handleRemoveFirstInstance = () => {
+        const firstInstance = getInstanceAt(0);
+        if (firstInstance) {
+            removeInstance(firstInstance);
+        }
+    };
+
+    const handleRemoveFirstByIndex = () => {
+        if (length > 0) {
+            removeInstanceAt(0);
+        }
+    };
+
+    const handleSwapItems = () => {
+        if (length >= 2) {
+            swap(0, 1);
+        }
+    };
+
+    return (
+        <div>
+            <RiveComponent style={{ width: '400px', height: '400px' }} />
+            {rive === null ? (
+                <div data-testid="loading-text">Loading…</div>
+            ) : (
+                <div>
+                    <div data-testid="list-length">Items: {length}</div>
+
+                    <div style={{ marginBottom: '10px', display: 'flex', gap: '8px', flexWrap: 'wrap' }}>
+                        <button
+                            data-testid="add-item-button"
+                            onClick={handleAddItem}
+                        >
+                            Add Item (End)
+                        </button>
+
+                        <button
+                            data-testid="add-item-at-button"
+                            onClick={handleAddItemAt}
+                            disabled={length === 0}
+                        >
+                            Add Item at Index 1
+                        </button>
+
+                        <button
+                            data-testid="remove-instance-button"
+                            onClick={handleRemoveFirstInstance}
+                            disabled={length === 0}
+                        >
+                            Remove First (by Instance)
+                        </button>
+
+                        <button
+                            data-testid="remove-index-button"
+                            onClick={handleRemoveFirstByIndex}
+                            disabled={length === 0}
+                        >
+                            Remove First (by Index)
+                        </button>
+
+                        <button
+                            data-testid="swap-button"
+                            onClick={handleSwapItems}
+                            disabled={length < 2}
+                        >
+                            Swap First Two
+                        </button>
+                    </div>
+
+                    <div data-testid="todo-items">
+                        {Array.from({ length }, (_, index) => (
+                            <TodoItemComponent
+                                key={index}
+                                index={index}
+                                todoItem={getInstanceAt(index)}
+                            />
+                        ))}
+                    </div>
+                </div>
+            )}
+        </div>
+    );
 };

src/hooks/useViewModelInstanceList.ts

@@ -1,4 +1,4 @@
-import { useCallback } from 'react';
+import { useCallback, useState } from 'react';
 import { ViewModelInstance, ViewModelInstanceList } from '@rive-app/canvas';
 import { UseViewModelInstanceListResult } from '../types';
 import { useViewModelInstanceProperty } from './useViewModelInstanceProperty';
@@ -15,13 +15,22 @@ export default function useViewModelInstanceList(
     viewModelInstance?: ViewModelInstance | null
 ): UseViewModelInstanceListResult {
 
+    // We track revision to trigger re-renders on list manipulation (e.g. addInstance, removeInstance, etc).
+    // This is mostly important for things like the swap function which wouldn't trigger a re-render otherwise.
+    // It also accounts for changes that happen within the Rive file itself rather than through the hook.
+    const [_revision, setRevision] = useState(0);
+
     const result = useViewModelInstanceProperty<ViewModelInstanceList, number, Omit<UseViewModelInstanceListResult, 'length'>>(
         path,
         viewModelInstance,
         {
             getProperty: useCallback((vm, p) => vm.list(p), []),
             getValue: useCallback((prop) => prop.length, []),
-            defaultValue: 0,
+            defaultValue: null,
+            onPropertyEvent: () => {
+                // This fires when the list changes in Rive
+                setRevision(prev => prev + 1);
+            },
             buildPropertyOperations: useCallback((safePropertyAccess) => ({
                 addInstance: (instance: ViewModelInstance) => {
                     safePropertyAccess(prop => prop.addInstance(instance));

src/index.ts

@@ -10,6 +10,7 @@ import useViewModelInstanceColor from './hooks/useViewModelInstanceColor';
 import useViewModelInstanceEnum from './hooks/useViewModelInstanceEnum';
 import useViewModelInstanceTrigger from './hooks/useViewModelInstanceTrigger';
 import useViewModelInstanceImage from './hooks/useViewModelInstanceImage';
+import useViewModelInstanceList from './hooks/useViewModelInstanceList';
 import useResizeCanvas from './hooks/useResizeCanvas';
 import useRiveFile from './hooks/useRiveFile';
 
@@ -28,6 +29,7 @@ export {
     useViewModelInstanceEnum,
     useViewModelInstanceTrigger,
     useViewModelInstanceImage,
+    useViewModelInstanceList,
     RiveProps,
 };
 export {