> ## Documentation Index
> Fetch the complete documentation index at: https://rive-transitions-2.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Data Binding

> Connect your code to bound editor elements using View Models

export const Demos = ({examples, runtime, columns = 2, children, childrenIndex = 0, learnByExample = false}) => {
  const examplesData = {
    accessibilityReducedMotion: {
      title: 'Reduced Motion Example',
      description: 'Strategies for respecting a user\'s reduced motion preferences.',
      riv: 'https://static.rive.app/rivs/accessibility_reduced_motion.riv',
      stateMachines: "State Machine 1",
      links: {
        editor: "https://rive.app/community/files/28077-53052-accessibility-reduced-motion"
      }
    },
    ikConstraint: {
      title: 'IK Constraints',
      description: 'Check out this example to see IK constraints in action.',
      image: "https://static.rive.app/docs/ik-constraint.gif",
      stateMachines: "State Machine 1",
      links: {
        editor: "https://rive.app/community/files/28080-53039-ik-constraint/"
      }
    },
    accessibilityReducedMotion: {
      title: 'Reduced Motion Example',
      description: 'Strategies for respecting a user\'s reduced motion preferences.',
      riv: 'https://static.rive.app/rivs/accessibility_reduced_motion.riv',
      stateMachines: "State Machine 1",
      links: {
        editor: "https://rive.app/community/files/28077-53052-accessibility-reduced-motion"
      }
    },
    cachingARiveFile: {
      title: 'Caching a Rive File',
      description: 'Load the .riv into memory once, use it multiple times.',
      riv: 'https://static.rive.app/rivs/rives_animated_emojis.riv',
      stateMachines: "State Machine 1",
      artboard: "Emoji_package",
      links: {
        web: "https://codesandbox.io/p/sandbox/rive-js-caching-a-rive-file-g675my?file=%2Fsrc%2Findex.ts%3A9%2C1",
        react: "https://codesandbox.io/p/sandbox/rive-react-caching-a-rive-file-53gmdf?file=%2Fsrc%2FApp.tsx"
      },
      source: ["https://rive.app/marketplace/24644-46045-caching-a-rive-file-at-runtime/"]
    },
    dataBindingArtboards: {
      title: 'Data Binding Artboards',
      description: 'Swap an artboard with another artboard from the same .riv or one loaded at runtime.',
      image: '/images/runtimes/rive-data-bind-components.webp',
      links: {
        web: 'https://codesandbox.io/p/sandbox/rive-js-data-binding-artboards-jx3pf9?file=%2Fsrc%2Findex.mjs%3A5%2C19',
        react: 'https://codesandbox.io/p/sandbox/rive-react-data-binding-artboards-kmvzh8?file=%2Fsrc%2FApp.tsx',
        flutter: 'https://github.com/rive-app/rive-flutter/blob/master/example/lib/examples/databinding_artboards.dart',
        reactNative: 'https://github.com/rive-app/rive-nitro-react-native/blob/main/example/src/demos/DataBindingArtboardsExample.tsx',
        android: "https://github.com/rive-app/rive-android/blob/master/app/src/main/java/app/rive/runtime/example/ComposeArtboardBindingActivity.kt"
      },
      source: ["https://rive.app/marketplace/24641-46042-data-binding-artboards/", "https://rive.app/marketplace/24642-47536-data-binding-artboards/"]
    },
    dataBindingImages: {
      title: 'Data Binding Images',
      description: 'Replace images at runtime using data binding images with javascript.',
      image: '/images/runtimes/rive-db-images.webp',
      links: {
        web: 'https://codesandbox.io/p/sandbox/objective-cohen-sqwh9q?file=%2Fsrc%2Findex.ts',
        flutter: 'https://github.com/rive-app/rive-flutter/blob/master/example/lib/examples/databinding_images.dart',
        android: "https://github.com/rive-app/rive-android/blob/master/app/src/main/java/app/rive/runtime/example/ComposeImageBindingActivity.kt"
      },
      source: ["https://rive.app/marketplace/25472-47537-data-binding-images/"]
    },
    dataBindingLists: {
      title: 'Data Binding Lists',
      description: 'Add, remove, edit, and swap items in your data binding list.',
      image: '/images/runtimes/rive-db-lists.webp',
      links: {
        web: 'https://codesandbox.io/p/sandbox/suspicious-hertz-2lg4m8?file=%2Fsrc%2Findex.ts',
        react: 'https://codesandbox.io/p/sandbox/rive-react-data-binding-lists-4msh9z?file=%2Fsrc%2FApp.tsx',
        flutter: 'https://github.com/rive-app/rive-flutter/blob/master/example/lib/examples/databinding_lists.dart',
        android: "https://github.com/rive-app/rive-android/blob/master/app/src/main/java/app/rive/runtime/example/ComposeListActivity.kt"
      },
      source: ["https://rive.app/marketplace/25474-47539-data-binding-lists/"]
    },
    dataBindingQuickStart: {
      title: "Data Binding",
      description: "Get started with Data Binding at runtime.",
      image: "/images/runtimes/rewards.gif",
      links: {
        flutter: "https://github.com/rive-app/rive-flutter/blob/master/example/lib/examples/databinding.dart",
        reactNative: "https://github.com/rive-app/rive-react-native/blob/main/example/app/(examples)/DataBinding.tsx",
        unity: "https://github.com/rive-app/rive-unity-examples/blob/main/getting-started/Assets/RewardsController.cs",
        apple: "https://github.com/rive-app/rive-ios/blob/main/Example-iOS/Source/Examples/SwiftUI/RewardsView.swift",
        android: "https://github.com/rive-app/rive-android/blob/master/app/src/main/java/app/rive/runtime/example/ComposeDataBindingActivity.kt"
      },
      source: ["https://rive.app/marketplace/25475-47540-data-binding-demo/"]
    },
    dataBindingSolos: {
      title: "Data Binding Solos",
      description: "Control solos at runtime using strings, numbers, or enums.",
      image: '/images/runtimes/data-binding-solos.gif',
      links: {
        react: "https://codesandbox.io/p/sandbox/rive-react-controlling-solos-at-runtime-ctcnlx?file=%2Fsrc%2FApp.tsx"
      },
      source: ["https://rive.app/marketplace/24643-46044-data-binding-solos/"]
    },
    googleAppAds: {
      title: "Google App Ads",
      description: "How to make an interactive Google App with Rive.",
      image: "/images/runtimes/google-app-ads.png",
      links: {
        mobile: "https://github.com/rive-app/rive-use-cases/tree/main/rive-google-ads"
      }
    },
    layouts: {
      title: "Responsive Layouts",
      description: "Create responsive layouts that adapt to different screen sizes.",
      riv: "https://static.rive.app/rivs/layouts_demo.riv",
      stateMachines: "State Machine 1",
      artboard: "Demo",
      links: {
        web: "https://codesandbox.io/p/devbox/rive-responsive-layout-js-forked-m77nlw",
        react: "https://codesandbox.io/p/devbox/rive-responsive-layouts-react-forked-nmpv39?file=%2Fsrc%2FApp.tsx",
        flutter: "https://github.com/rive-app/rive-flutter/blob/master/example/lib/examples/responsive_layouts.dart",
        reactNative: "https://github.com/rive-app/rive-react-native/blob/main/example/app/(examples)/ResponsiveLayout.tsx",
        android: "https://github.com/rive-app/rive-android/blob/master/app/src/main/java/app/rive/runtime/example/ComposeLayoutActivity.kt"
      },
      source: ["https://rive.app/marketplace/24638-46038-layouts-demo/"]
    },
    fontsHostedCompressed: {
      title: 'Load a Compressed Font for Web',
      description: 'Dynamically load a font asset from a hosted location with compression.',
      image: '/images/runtimes/brotli-compressed-fonts.webp',
      links: {
        react: 'https://codesandbox.io/p/sandbox/prod-sound-6yc5xl?file=%2Fsrc%2FApp.tsx%3A19%2C1'
      },
      source: ["https://rive.app/marketplace/25473-47538-loading-compressed-fonts-web/"]
    },
    quickStart: {
      title: "Data Binding Quick Start",
      image: '/images/runtimes/quick-start.gif',
      description: 'Load and control your Rive (.riv) file.',
      links: {
        web: 'https://codesandbox.io/p/sandbox/rive-quick-start-js-xmwcm6?file=%2Fsrc%2Findex.ts',
        react: 'https://codesandbox.io/p/sandbox/rive-react-quick-start-4xy76h?file=%2Fsrc%2FApp.tsx%3A77%2C14',
        reactJs: 'https://codesandbox.io/p/devbox/rive-react-vanilla-js-quick-start-kz66t4?file=%2Fsrc%2FApp.tsx%3A53%2C7',
        reactNative: 'https://github.com/rive-app/rive-nitro-react-native/blob/main/example/src/demos/QuickStart.tsx',
        unity: '/game-runtimes/unity/tutorials/health-bar'
      },
      source: ["https://rive.app/marketplace/24637-46037-health-bar-data-binding-quick-start/"]
    },
    quickStartReact: {
      title: "Data Binding Quick Start",
      image: '/images/runtimes/quick-start.gif',
      description: 'Load and control your Rive (.riv) file.',
      links: {
        react: 'https://codesandbox.io/p/sandbox/rive-react-quick-start-4xy76h?file=%2Fsrc%2FApp.tsx%3A77%2C14',
        reactJs: 'https://codesandbox.io/p/devbox/rive-react-vanilla-js-quick-start-kz66t4?file=%2Fsrc%2FApp.tsx%3A53%2C7'
      },
      source: ["https://rive.app/marketplace/24637-46037-health-bar-data-binding-quick-start/"]
    },
    scriptingDrawingShapes: {
      title: "Drawing with Scripting",
      image: "https://static.rive.app/docs/drawing-demo.png",
      description: "Draw a squirkle, a star, and an animated wave with scripting.",
      links: {
        editor: "https://rive.app/community/files/25751-48087-drawing-shapes-with-scripting"
      }
    },
    scriptingMasonry: {
      title: "Masonry Layout",
      image: "https://static.rive.app/docs/masonry.png",
      description: "Create a masonry layout using a Layout script.",
      links: {
        editor: "https://rive.app/community/files/25826-masonry-layout/"
      }
    },
    scriptingParticleEmitter: {
      title: "Particle Emitter",
      riv: "https://static.rive.app/rivs/particle-demo.riv",
      artboard: "Demo",
      description: "A small, self contained particle system for Rive node and layout scripts.",
      links: {
        editor: "https://rive.app/community/files/28062-53012-particle-librar/"
      }
    },
    scriptingTippingConverter: {
      title: "Custom Converter",
      image: "https://static.rive.app/docs/tipping-scripting-converter.gif",
      description: "Calculate the bill total using the converter's input value added to data binding values.",
      links: {
        editor: "https://uat.rive.app/community/files/610-1126-custom-converter-with-scripting"
      }
    },
    scriptingUnitTesting: {
      title: "Unit Testing",
      image: "https://static.rive.app/docs/scripting-default-thumb.png",
      description: "This hands-on example demonstrates unit testing rgbToHex and hexToRgb color utilities.",
      links: {
        editor: "https://rive.app/community/files/25752-48088-test-script"
      }
    },
    scriptingSnakeGame: {
      title: "Snake - Complete Game",
      image: "https://static.rive.app/docs/snake-game.png",
      description: "Check out this complete game built entirely with Rive using scripting.",
      links: {
        editor: "https://rive.app/community/files/25748-48110-snake-game/"
      }
    },
    scriptingMultiTouch: {
      title: "Tracking Multi-touch",
      image: "https://static.rive.app/docs/scripting-default-thumb.png",
      description: "Keep track of every finger.",
      links: {
        editor: "https://rive.app/community/files/25754-48090-multi-touch-with-scripting"
      }
    },
    scriptingNestedPointers: {
      title: "Nested Pointer Events",
      image: "https://static.rive.app/docs/scripting-default-thumb.png",
      description: "Pass pointer events from the parent component to the instantiated children.",
      links: {
        editor: "https://rive.app/community/files/25750-48086-scripting-nested-pointer-events/"
      }
    },
    scriptingBoilPathEffect: {
      title: "Boiling Path Effect",
      image: "https://static.rive.app/docs/boiling-effect.gif",
      description: "Apply a boiling effect to any path using scripting.",
      links: {
        editor: "https://rive.app/community/files/25767-48113-scripting-path-effect-boil"
      }
    },
    scriptingTextPathEffect: {
      title: "Text Path Effect",
      image: "https://static.rive.app/docs/text-path-effect.gif",
      description: "Control a text path using scripting.",
      links: {
        editor: "https://rive.app/community/files/25823-text-path-effects/"
      }
    },
    scriptingDrawImages: {
      title: "Render an Image with Scripting",
      image: "https://static.rive.app/docs/render-image-with-scripting.jpg",
      description: "Draw an image, give it transforms, control its mesh, and add clipping all through scripting.",
      links: {
        editor: "https://rive.app/community/files/26406-draw-an-image-with-scripting"
      }
    },
    scriptingSlotMachine: {
      title: "Slot Machine - Complete Game",
      image: "https://static.rive.app/docs/slot-machine.png",
      description: "Build a complete casino game using scripting.",
      links: {
        editor: "https://rive.app/community/files/25759-slot-machine-game-with-scripting/"
      }
    },
    scriptingLists: {
      title: "Scripting Lists",
      image: "/images/runtimes/rive-db-lists.webp",
      description: "Add, remove, edit, and swap items in your data binding list using Rive scripting.",
      links: {
        editor: "https://rive.app/community/files/27098-51051-scripting-lists"
      }
    },
    scriptingPlinko: {
      title: "Plinko - Complete Game",
      image: "https://static.rive.app/docs/scripting-plinko-game.png",
      description: "Build a complete Plinko game using Layout, Node, and Path Effect scripts.",
      links: {
        editor: "https://rive.app/marketplace/25772-blinko-scripted-game/"
      }
    },
    constraints: {
      title: "Constraints",
      image: "https://static.rive.app/docs/constraints.gif",
      description: "Transform, Translate, Scale, and Rotation Constraints.",
      links: {
        editor: "https://rive.app/community/files/28081-53040-constraints/"
      }
    }
  };
  const runtimesInOrder = ['web', 'react', 'reactJs', 'reactNative', 'flutter', 'apple', 'android', 'unity', 'unreal', 'mobile', 'editor'];
  const runtimeTitles = {
    web: 'Web',
    reactJs: 'React (Imperative)',
    react: 'React',
    reactNative: "React Native",
    flutter: 'Flutter',
    apple: 'Apple',
    android: 'Android',
    unity: 'Unity',
    unreal: 'Unreal',
    mobile: 'Mobile',
    editor: 'Try in Rive'
  };
  const riveInstances = useRef([]);
  const initRives = () => {
    const rive = window.rive;
    examples.forEach(example => {
      const {riv, stateMachines = "State Machine 1", artboard} = examplesData[example];
      if (riv) {
        const canvasId = `rive-canvas-${example}`;
        const canvas = document.getElementById(canvasId);
        if (canvas) {
          const r = new rive.Rive({
            src: riv,
            stateMachines,
            canvas,
            artboard,
            autoBind: true,
            autoplay: true,
            Layout: new rive.Layout({
              fit: rive.Fit.Layout
            }),
            onLoad: () => {
              r.resizeDrawingSurfaceToCanvas();
              riveInstances.current.push(r);
            }
          });
        }
      }
    });
  };
  useEffect(() => {
    if (window.rive) {
      initRives();
      return;
    }
    const checkRive = () => {
      if (window.rive) {
        initRives();
        window.removeEventListener("rive-loaded", checkRive);
      }
    };
    const handleResize = () => {
      riveInstances.current.forEach(instance => {
        instance.resizeDrawingSurfaceToCanvas();
      });
    };
    window.addEventListener("rive-loaded", checkRive);
    window.addEventListener("resize", handleResize);
    return () => {
      window.removeEventListener("rive-loaded", checkRive);
      window.removeEventListener("resize", handleResize);
      riveInstances.current.forEach(instance => {
        instance.cleanup();
      });
    };
  }, []);
  const RuntimeLink = ({link, runtime}) => {
    if (!link) return null;
    if (runtime === 'editor') {
      link = `${link}?utm_source=docs&utm_medium=docs_demo_card`;
    }
    return <a href={link} target="_blank" className="cursor-pointer border border-neutral-600 hover:border-white rounded-[4px] text-14 py-1 px-5 mr-[10px] mb-[10px]">
        {runtimeTitles[runtime]}
      </a>;
  };
  const CardContainer = ({children: content}) => {
    return <div className="flex flex-col card block font-normal group relative my-2 ring-2 ring-transparent rounded-2xl bg-white dark:bg-background-dark border border-gray-950/10 dark:border-white/10 overflow-hidden w-full">
        {content}
      </div>;
  };
  const getSrc = imageSrc => {
    if (location.hostname === "localhost" && imageSrc.startsWith("/images/")) {
      return imageSrc;
    } else if (imageSrc.startsWith('https:')) {
      return imageSrc;
    }
    return `https://rive.app/docs${imageSrc}`;
  };
  return <div className={`
        card-group not-prose grid gap-x-4
        grid-cols-1
        ${columns >= 2 && "md:grid-cols-2"}
        ${columns >= 3 && "xl:grid-cols-3 xl:w-[67rem] xl:max-w-[calc(100vw-25rem)]"}
      `}>
      {examples.map((example, index) => {
    const {title, image, links, description, source, riv} = examplesData[example];
    const canvasId = `rive-canvas-${example}`;
    return <>
            {index === childrenIndex && children}
            <CardContainer key={canvasId}>
              <div className="w-full h-0 relative pb-[75%]">
                <div className="absolute inset-0">
                  {image && <img alt={title} className="w-full object-cover object-center" src={getSrc(image)} />}

                  {riv && !image && <canvas id={canvasId} style={{
      width: "100%",
      height: "100%"
    }} />}
                </div>
              </div>
              <div className="flex flex-grow flex-col px-6 py-5 relative" data-component-part="card-content-container">
                <div className="flex flex-col grow">
                  <h2 className="not-prose font-semibold text-base text-gray-800 dark:text-white" data-component-part="card-title">{learnByExample ? "Learn by Example" : title}</h2>

                  <div className="flex flex-col grow prose mt-1 font-normal text-sm leading-6 text-gray-600 dark:text-gray-400" data-component-part="card-content">
                    <div className="grow flex flex-col">
                      {description && !learnByExample && <p>{description}</p>}
                      {source && source.length > 0 && <p className="mt-3">
                            {source.map((item, index) => {
      if (source.length == 1) {
        return <>Open the <a href={item}>Rive file</a>.</>;
      }
      if (index == 0) {
        return <>Open <a href={item}>Rive file 1</a></>;
      }
      return <>, <a href={item}>file {index + 1}</a></>;
    })}
                          </p>}
                    </div>
                    {<div className="mt-6 flex flex-wrap">
                        {runtimesInOrder.map(currentRuntime => {
      if (runtime && currentRuntime !== runtime) return;
      return <RuntimeLink key={currentRuntime} runtime={currentRuntime} link={links[currentRuntime]} />;
    })}
                      </div>}
                  </div>
                </div>
              </div>
            </CardContainer>
          </>;
  })}
    </div>;
};

export const YouTube = ({id, timestamp}) => {
  const videoSrc = timestamp ? `https://www.youtube.com/embed/${id}?start=${timestamp}` : `https://www.youtube.com/embed/${id}`;
  return <iframe width="100%" height="400" src={videoSrc} title="YouTube video player" frameBorder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerPolicy="strict-origin-when-cross-origin" allowFullScreen />;
};

Before engaging with the runtime data binding APIs, it is important to familiarize yourself with the core concepts presented in the [Overview](/editor/data-binding/overview).

<Demos examples={["quickStart"]} runtime="web" />

# View Models

View models describe a set of properties, but cannot themselves be used to get or set values - that is the role of [view model instances](#view-model-instances).

To begin, we need to get a reference to a particular view model. This can be done either by index, by name, or the default for a given artboard, and is done from the Rive file. The default option refers to the view model assigned to an artboard by the dropdown in the editor.

Access a View Model from the created Rive object in the `onLoad` callback:

```typescript theme={null}
const r = new rive.Rive({
    onLoad: () => {
        // The Rive object is now loaded and ready to use.
    }
});
```

Once Rive is loaded, you can access the view models using the following methods:

```typescript theme={null}
// Get reference by name
const namedVM = r.viewModelByName("My View Model");

// Get reference by index
for (let i = 0; i < r.viewModelCount; i++) {
    const indexedVM = r.viewModelByIndex(i);
}

// Get reference to the default view model
const defaultVM = r.defaultViewModel();
```

Alternatively, if you have access to the underlying `RiveFile` object you can access the above methods on the file.

```typescript theme={null}
const file = new RiveFile(/** ... */);
await file.init();
const vmFromFile = file.viewModelByName("My View Model");

// Or grab the ViewModel via other means from the RiveFile underlying instance
const fileInstance = file.getInstance();
const namedVM = fileInstance.viewModelByName("My View Model");
const indexedVM = fileInstance.viewModelByIndex(0);
const defaultVM = fileInstance.defaultArtboardViewModel(artboard);
```

# View Model Instances

Once we have a reference to a view model, it can be used to create an instance. When creating an instance, you have four options:

1. Create a blank instance - Fill the properties of the created instance with default values as follows:

   | Type              | Value           |
   | ----------------- | --------------- |
   | Number            | 0               |
   | String            | Empty string    |
   | Boolean           | False           |
   | Color             | 0xFF000000      |
   | Trigger           | Untriggered     |
   | Enum              | The first value |
   | Image             | No image        |
   | Artboard          | No artboard     |
   | List              | Empty list      |
   | Nested view model | Null            |

2. Create the default instance - Use the instance labelled "Default" in the editor. Usually this is the one a designer intends as the primary one to be used at runtime.

3. Create by index - Using the order returned when iterating over all available instances. Useful when creating multiple instances by iteration.

4. Create by name - Use the editor's instance name. Useful when creating a specific instance.

<Note>
  In some samples, due to the wordiness of "view model instance", we use the abbreviation "VMI", as well as "VM" for "view model".
</Note>

```typescript theme={null}
// Create a blank instance from a view model (ViewModel)
const vmiBlank = viewModel.instance();

// Create a default instance from a view model (ViewModel)
const vmiDefault = viewModel.defaultInstance();

// Create an instance by index from a view model (ViewModel)
for (let i = 0; i < viewModel.instanceCount; i++) {
    const vmiIndexed = viewModel.instanceByIndex(i);
}

// Create an instance by name from a view model (ViewModel)
const vmiNamed = viewModel.instanceByName("My Instance");
```

### Binding

The created instance can then be assigned to a state machine or artboard. This establishes the bindings set up at edit time.

It is preferred to assign to a state machine, as this will automatically apply the instance to the artboard as well. Only assign to an artboard if you are not using a state machine, i.e. your file is static or uses linear animations.

<Note>
  The initial values of the instance are not applied to their bound elements until the state machine or artboard advances.
</Note>

```typescript theme={null}
const r = new rive.Rive({
    autoBind: false, // This should be set to false (default)
    onLoad: () => {
        const vm = r.viewModelByName("My View Model");
        const vmi = vm.instanceByName("My Instance");

        // Manually bind by applying the instance to the state machine and artboard
        r.bindViewModelInstance(vmi);
    }
});
```

### Auto-Binding

Alternatively, you may prefer to use auto-binding. This will automatically bind the default view model of the artboard using the default instance to both the state machine and the artboard. The default view model is the one selected on the artboard in the editor dropdown. The default instance is the one marked "Default" in the editor.

```typescript {4} theme={null}
const r = new rive.Rive({
   src: "my_rive_file.riv",
   canvas: document.getElementById("canvas"),
   autoBind: true,
   onLoad: () => {
       // Access the current instance that was auto-bound
       let boundInstance = r.viewModelInstance;
   }
});
```

### Get View Model from Instance

When working with view model instances, you may want to get a reference to the view model the instance came from so you can dynamically create more instances of the same type (i.e. creating instances from lists).
To do so, first grab the name of the view model the instance came from via the `.viewModelName` property:

```ts theme={null}
const vmi = r.viewModelInstance;
const vmName = vmi.viewModelName;
```

Then, once you have the name, you can get a reference to the view model itself and create instances as needed.

```ts theme={null}
const vmi = r.viewModelInstance;
const mainListProp = vmi.list("todos") as ViewModelInstanceList;
const vmName = mainListProp.instanceAt(0)?.viewModelName;

const itemVmReference = r.viewModelByName(vmName);
const instanceCopies = [];
for (let i = 0; i < 10; i++) {
    instanceCopies.push(itemVmReference.defaultInstance());
}
```

# Properties

A property is a value that can be read, set, or observed on a view model instance. Properties can be of the following types:

| Type                   | Supported |
| ---------------------- | --------- |
| Floating point numbers | ✅         |
| Booleans               | ✅         |
| Triggers               | ✅         |
| Strings                | ✅         |
| Enumerations           | ✅         |
| Colors                 | ✅         |
| Nested View Models     | ✅         |
| Lists                  | ✅         |
| Images                 | ✅         |
| Artboards              | ✅         |

For more information on version compatibility, see the [Feature Support](/feature-support) page.

### Listing Properties

Property descriptors can be inspected on a view model to discover at runtime which are available. These are not the mutable properties themselves though - once again those are on instances. These descriptors have a type and name.

```typescript theme={null}
    // A list of properties on a view model (ViewModel)
    const properties = viewModel.properties;
    console.log(properties);
```

### Reading and Writing Properties

References to these properties can be retrieved by name or path.

Some properties are mutable and have getters, setters, and observer operations for their values. Getting or observing the value will retrieve the latest value set on that property's binding, as of the last state machine or artboard advance. Setting the value will update the value and all of its bound elements.

<Note>
  After setting a property's value, the changes will not apply to their bound elements until the state machine or artboard advances.
</Note>

```typescript theme={null}
const r = new rive.Rive({
    autoBind: true,
    onLoad: () => {
        // Access the current instance that was auto-bound
        let vmi = r.viewModelInstance;

        // Booleans
        const booleanProperty = vmi.boolean("My Boolean Property");
        const booleanValue = booleanProperty.value;
        booleanProperty.value = true;

        // Strings
        const stringProperty = vmi.string("My String Property");
        const stringValue = stringProperty.value;
        stringProperty.value = "Hello, Rive!";

        // Numbers
        const numberProperty = vmi.number("My Number Property");
        const numberValue = numberProperty.value;
        numberProperty.value = 10;

        // Colors
        const colorProperty = vmi.color("My Color Property");
        const colorValue = colorProperty.value;
        colorProperty.value = 0xFF000000; // Set color to black with 100% opacity

        // Other ways to set color
        colorProperty.rgb(255, 0, 0); // Set RGB to red
        colorProperty.rgba(255, 0, 0, 128); // Set RGBA to red with 50% opacity
        colorProperty.argb(128, 255, 0, 0); // Set ARGB to red with 50% opacity
        colorProperty.opacity(0.5); // Set opacity to 50%

        // Triggers
        const triggerProperty = vmi.trigger("My Trigger Property");
        triggerProperty.trigger();

        // Enumerations
        const enumProperty = vmi.enum("My Enum Property");
        const enumValue = enumProperty.value;
        enumProperty.value = "Option1";
    }
});
```

### Nested Property Paths

View models can have properties of type view model, allowing for arbitrary nesting. You can chain property calls on each instance starting from the root until you get to the property of interest. Alternatively, you can do this through a path parameter, which is similar to a URI in that it is a forward slash delimited list of property names ending in the name of the property of interest.

```typescript theme={null}
const r = new rive.Rive({
    autoBind: true,
    onLoad: () => {
        // Access the current instance that was auto-bound
        let vmi = r.viewModelInstance;

        const nestedNumberByChain = vmi
            .viewModel("My Nested View Model")
            .viewModel("My Second Nested VM")
            .number("My Nested Number");

        const nestedNumberByPath = vmi.number("My Nested View Model/My Second Nested VM/My Nested Number");
    }
});
```

### Observability

You can observe changes over time to property values, either by using listeners or a platform equivalent method. Once observed, you will be notified when the property changes are applied by a state machine advance, whether that is a new value that has been explicitly set or if the value was updated as a result of a binding.

Adding an observer to a property is done by calling the `on` method on the property.

```typescript theme={null}
public on(callback: EventCallback)
```

The observer can be removed by calling the `off` method on the property and passing the callback function. Alternatively, you can call `off()` without any arguments to remove all observers.

```typescript theme={null}
public off(callback?: EventCallback)
```

Example:

```typescript theme={null}
const r = new rive.Rive({
    autoBind: true,
    onLoad: () => {
        // Access the current instance that was auto-bound
        let vmi = r.viewModelInstance;
        const numberProperty = vmi.number("My Number Property");
        // Observe
        numberProperty.on((event) => {
            console.log(event.data);
        });
        // Remove all listener when done
        numberProperty.off();
    }
});
```

### Images

Image properties let you set and replace raster images at runtime, with each instance of the image managed independently. For example, you could build an avatar creator and dynamically update features — like swapping out a hat — by setting a view model's image property.

<Demos examples={['dataBindingImages']} runtime="web" />

```js theme={null}
const randomImageAsset = (imageProperty) => {
    fetch("https://picsum.photos/300/500").then(async (res) => {
        // Decode the image from the response. This object is used to set the image property.
        const image = await rive.decodeImage(
            new Uint8Array(await res.arrayBuffer())
        );
        imageProperty.value = image;
        // Rive will automatically clean this up. But it's good practice to dispose this manually
        // after you have already set the decoded image. Don't call `unref` if you intend
        // to use the decoded asset again.
        image.unref();
    });
};

const r = new rive.Rive({
    autoBind: true,
    onLoad: () => {
        // Access the current instance that was auto-bound
        let vmi = r.viewModelInstance;

        // Get the image property by name
        var imageProperty = vmi.image("bound_image");

        // Load random image
        randomImageAsset(imageProperty);

        // Clear the image to render nothing
        imageProperty.value = null;
    }
});
```

### Lists

List properties let you manage a dynamic set of view model instances at runtime. For example, you can build a TODO app where users can add and remove tasks in a scrollable Layout.

See the [Editor section](/editor/data-binding/lists) on creating data bound lists.

A single list property can include different view model types, with each view model tied to its own Component, making it easy to populate a list with a variety of Component instances.

With list properties, you can:

* Add a new view model instance (optionally at an index)
* Remove an existing view model instance (optionally by index)
* Swap two view model instances by index
* Get the size of a list

For more information on list properties, see the [Data Binding List Property](/editor/data-binding/lists#view-model-list-property) editor documentation.

<Demos examples={['dataBindingLists']} runtime="web" />

```javascript theme={null}
const r = new rive.Rive({
    autoBind: true,
    onLoad: () => {
        // Access the current instance that was auto-bound
        let vmi = r.viewModelInstance;

        // Get the list property by name
        var list = vmi.list("todos");
        console.log("length: ", list.length);

        // Get the view model
        var todoItemVM = r.viewModelByName("TodoItem");

        // Create a blank instance from the view model.
        // Do this for each new item you want to add.
        var myTodo = todoItemVM.instance();
        myTodo.string("description").value = "Buy groceries";

        // Add the newly created instance to the list
        list.addInstance(myTodo);

        // Remove a specific instance from the list
        list.removeInstance(myTodo);

        // Swap two instances in the list at index 0 and 1
        list.swap(0, 1);

        // Remove instance at index 0
        list.removeInstanceAt(0);
    }
});
```

### Artboards

Artboard properties allows you to swap out entire components at runtime. This is useful for creating modular components that can be reused across different designs or applications, for example:

* Creating a skinning system that supports a large number of variations, such as a character creator where you can swap out different body parts, clothing, and accessories.
* Creating a complex scene that is a composition of various artboards loaded from various different Rive files (drawn to a single canvas/texture/widget).
* Reducing the size (complexity) of a single Rive file by breaking it up into smaller components that can be loaded on demand and swapped in and out as needed.

<Demos examples={["dataBindingArtboards"]} runtime="web" />

```typescript theme={null}
let artboardProperty = null;
let characterArtboard = null;

function attachCharacter() {
    // If the artboard property and the character artboard, both exist, set the artboard
    if (characterArtboard && artboardProperty) {
        artboardProperty.value = characterArtboard;
    }
}

const r = new Rive({
    src: "swap_character_main.riv",
    autoplay: true,
    canvas: el,
    autoBind: true,
    layout: new Layout({
        fit: Fit.Layout,
        layoutScaleFactor: 0.5,
    }),
    stateMachines: "State Machine 1",
    onLoad: () => {
        r.resizeDrawingSurfaceToCanvas();

        const vmi = r.viewModelInstance;
        artboardProperty = vmi.artboard("Artboard property");

        attachCharacter();
    },
    onLoadError: () => {
        console.log("error");
    },
});

// Load an external artboard
const assetsFile = new RiveFile({
    src: "swap_character_assets.riv",
    onLoad: () => {
        characterArtboard = assetsFile.getBindableArtboard("Character 1");
        attachCharacter();
    },
    onLoadError: () => {
        console.log("error");
    },
});
assetsFile.init();
```

In the example above, we load from a separate `swap_character_assets.riv` file to get the `Character 1` bindable artboard. We can then use this value in the main `swap_character_main.riv` file by setting the value of the `artboardProperty` to the loaded `characterArtboard`. This allows us to swap out the artboard being used in the main file at runtime.
Additionally, you can set an external `ViewModelInstance` to that bindable artboard via the `.viewModel` setter.

### Enums

Enums properties come in two flavors: system and user-defined. In practice, you will not need to worry about the distinction, but just be aware that system enums are available in any Rive file that binds to an editor-defined enum set, representing options from the editor's dropdowns, where user-defined enums are those defined by a designer in the editor.

Enums are string typed. The Rive file contains a list of enums. Each enum in turn has a name and a list of strings.

```typescript theme={null}
const r = new rive.Rive({
    onLoad: () => {
        const enums = r.enums();

        console.log(enums);
    }
});
```

# Examples

<YouTube id="y7glxOIFEjg" />

<YouTube id="1WFtGX2coXM" />