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Using a State Management Library

In this guide we are explaining how you could use React Flow with the state management library Zustand. We will build a little app where every node has a color chooser that updates the background color of the specific node. In this guide we are are using Zustand, because we are also using it internally for React Flow, but of course you can use any other library like Redux, Recoil or Jotai as well. For this guide we expect you to know about the core concepts of React Flow and how to implement custom nodes.

As you might have seen in the previous guides and examples, React Flow can easily be used with a local state for handling the nodes and edges of your diagram. When your app grows and you want to alter your state from within your nodes for examples, things can get messy. To avoid passing down functions through the node data field, you could use a React context or add a state management library as explained in this guide.

Install Zustand

As mentioned above we are using Zustand in this example. Zustand is a bit like Redux, so you have a central store, actions to alter your state and hooks to access your state. You can install Zustand via:

npm install --save zustand

Create a Store

Zustand lets us create a hook for accessing our store easily. We put our nodes and edges and the onNodesChange, onEdgesChange and onConnect functions in the store in order to get the basic interactivity for our diagram:

That's the basic setup. We now have a store with the nodes and edges that can handle the changes triggered by React Flow. When you take a look at the App.tsx file, you can see that its nice and clean. All the data and actions are now part of the store and can easily be accessed with the useStore hook.

Implement a Color Change Action

We add a new updateNodeColor action to update the data.color field of a specific node. For this we pass the node id and the new color to the action, iterate over the nodes and update the matching one with the new color:

updateNodeColor: (nodeId: string, color: string) => {
set({
nodes: get().nodes.map((node) => {
if (node.id === nodeId) {
// it's important to create a new object here, to inform React Flow about the changes
node.data = { ...node.data, color };
}

return node;
}),
});
};

This new action can now be used in a React component like this:

const updateNodeColor = useStore((s) => s.updateNodeColor);
...
<button onClick={() => updateNodeColor(nodeId, color)} />;

Add a Color Chooser Node

In this last step we implement the ColorChooserNode component and call the updateNodeColor when the user changes the color. The custom part of the color chooser node is the color input.

<input
type="color"
defaultValue={data.color}
onChange={(evt) => updateNodeColor(id, evt.target.value)}
className="nodrag"
/>

We add the nodrag class name so that the user don't drag the node by mistake when changing the color and call the updateNodeColor in the onChange event handler.

You can now click on a color chooser and change the background of a node.