Name:
interface
Value:
Amplify has re-imagined the way frontend developers build fullstack applications. Develop and deploy without the hassle.

Page updated May 2, 2024

Optimistic UI

Amplify Data can be used with TanStack Query to implement optimistic UI, allowing CRUD operations to be rendered immediately on the UI before the request roundtrip has completed. Using Amplify Data with TanStack additionally makes it easy to render loading and error states, and allows you to rollback changes on the UI when API calls are unsuccessful.

In the following examples we'll create a list view that optimistically renders newly created items, and a detail view that optimistically renders updates and deletes.

For more details on TanStack Query, including requirements, supported browsers, and advanced usage, see the TanStack Query documentation. For complete guidance on how to implement optimistic updates with TanStack Query, see the TanStack Query Optimistic UI Documentation. For more on Amplify Data, see the API documentation.

To get started, run the following command in an existing Amplify project with a React frontend:

Terminal
# Install TanStack Query
npm i @tanstack/react-query @tanstack/react-query-devtools

Modify your Data schema to use this "Real Estate Property" example:

amplify/data/resource.ts
const schema = a.schema({
RealEstateProperty: a.model({
name: a.string().required(),
address: a.string(),
}).authorization(allow => [allow.guest()])
})
export type Schema = ClientSchema<typeof schema>;
export const data = defineData({
schema,
authorizationModes: {
defaultAuthorizationMode: 'iam',
},
});

Save the file and run npx ampx sandbox to deploy the changes to your backend cloud sandbox. For the purposes of this guide, we'll build a Real Estate Property listing application.

Next, at the root of your project, add the required TanStack Query imports, and create a client:

src/main.tsx
import React from 'react'
import ReactDOM from 'react-dom/client'
import App from './App.tsx'
import './index.css'
import { Amplify } from 'aws-amplify'
import outputs from '../amplify_outputs.json'
import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
import { ReactQueryDevtools } from "@tanstack/react-query-devtools";
Amplify.configure(outputs)
const queryClient = new QueryClient()
ReactDOM.createRoot(document.getElementById('root')!).render(
<React.StrictMode>
<QueryClientProvider client={queryClient}>
<App />
<ReactQueryDevtools initialIsOpen={false} />
</QueryClientProvider>
</React.StrictMode>,
)

TanStack Query Devtools are not required, but are a useful resource for debugging and understanding how TanStack works under the hood. By default, React Query Devtools are only included in bundles when process.env.NODE_ENV === 'development', meaning that no additional configuration is required to exclude them from a production build. For more information on the TanStack Query Devtools, visit the TanStack Query Devtools docs

For the complete working example, including required imports and React component state management, see the Complete Example below.

How to use TanStack Query query keys with the Amplify Data API

TanStack Query manages query caching based on the query keys you specify. A query key must be an array. The array can contain a single string or multiple strings and nested objects. The query key must be serializable, and unique to the query's data.

When using TanStack to render optimistic UI with Amplify Data, you must use different query keys depending on the API operation. When retrieving a list of items, a single string is used (e.g. queryKey: ["realEstateProperties"]). This query key is also used to optimistically render a newly created item. When updating or deleting an item, the query key must also include the unique identifier for the record being deleted or updated (e.g. queryKey: ["realEstateProperties", newRealEstateProperty.id]).

For more detailed information on query keys, see the TanStack Query documentation.

Optimistically rendering a list of records

To optimistically render a list of items returned from the Amplify Data API, use the TanStack useQuery hook, passing in the Data API query as the queryFn parameter. The following example creates a query to retrieve all records from the API. We'll use realEstateProperties as the query key, which will be the same key we use to optimistically render a newly created item.

src/App.tsx
import type { Schema } from '../amplify/data/resource'
import { generateClient } from 'aws-amplify/data'
import { useQuery } from '@tanstack/react-query'
const client = generateClient<Schema>();
function App() {
const {
data: realEstateProperties,
isLoading,
isSuccess,
isError: isErrorQuery,
} = useQuery({
queryKey: ["realEstateProperties"],
queryFn: async () => {
const response = await client.models.RealEstateProperty.list();
const allRealEstateProperties = response.data;
if (!allRealEstateProperties) return null;
return allRealEstateProperties;
},
});
// return ...
}

Optimistically rendering a newly created record

To optimistically render a newly created record returned from the Amplify Data API, use the TanStack useMutation hook, passing in the Amplify Data API mutation as the mutationFn parameter. We'll use the same query key used by the useQuery hook (realEstateProperties) as the query key to optimistically render a newly created item. We'll use the onMutate function to update the cache directly, as well as the onError function to rollback changes when a request fails.

import { generateClient } from 'aws-amplify/api'
import type { Schema } from '../amplify/data/resource'
import { useQueryClient, useMutation } from '@tanstack/react-query'
const client = generateClient<Schema>()
function App() {
const queryClient = useQueryClient();
const createMutation = useMutation({
mutationFn: async (input: { name: string, address: string }) => {
const { data: newRealEstateProperty } = await client.models.RealEstateProperty.create(input)
return newRealEstateProperty;
},
// When mutate is called:
onMutate: async (newRealEstateProperty) => {
// Cancel any outgoing refetches
// (so they don't overwrite our optimistic update)
await queryClient.cancelQueries({ queryKey: ["realEstateProperties"] });
// Snapshot the previous value
const previousRealEstateProperties = queryClient.getQueryData([
"realEstateProperties",
]);
// Optimistically update to the new value
if (previousRealEstateProperties) {
queryClient.setQueryData(["realEstateProperties"], (old: Schema["RealEstateProperty"]["type"][]) => [
...old,
newRealEstateProperty,
]);
}
// Return a context object with the snapshotted value
return { previousRealEstateProperties };
},
// If the mutation fails,
// use the context returned from onMutate to rollback
onError: (err, newRealEstateProperty, context) => {
console.error("Error saving record:", err, newRealEstateProperty);
if (context?.previousRealEstateProperties) {
queryClient.setQueryData(
["realEstateProperties"],
context.previousRealEstateProperties
);
}
},
// Always refetch after error or success:
onSettled: () => {
queryClient.invalidateQueries({ queryKey: ["realEstateProperties"] });
},
});
// return ...
}

Querying a single item with TanStack Query

To optimistically render updates on a single item, we'll first retrieve the item from the API. We'll use the useQuery hook, passing in the get query as the queryFn parameter. For the query key, we'll use a combination of realEstateProperties and the record's unique identifier.

import { generateClient } from 'aws-amplify/data'
import type { Schema } from '../amplify/data/resource'
import { useQuery } from '@tanstack/react-query'
const client = generateClient<Schema>()
function App() {
const currentRealEstatePropertyId = "SOME_ID"
const {
data: realEstateProperty,
isLoading,
isSuccess,
isError: isErrorQuery,
} = useQuery({
queryKey: ["realEstateProperties", currentRealEstatePropertyId],
queryFn: async () => {
if (!currentRealEstatePropertyId) { return }
const { data: property } = await client.models.RealEstateProperty.get({
id: currentRealEstatePropertyId,
});
return property;
},
});
}

Optimistically render updates for a record

To optimistically render Amplify Data updates for a single record, use the TanStack useMutation hook, passing in the update mutation as the mutationFn parameter. We'll use the same query key combination used by the single record useQuery hook (realEstateProperties and the record's id) as the query key to optimistically render the updates. We'll use the onMutate function to update the cache directly, as well as the onError function to rollback changes when a request fails.

When directly interacting with the cache via the onMutate function, the newRealEstateProperty parameter will only include fields that are being updated. When calling setQueryData, include the previous values for all fields in addition to the newly updated fields to avoid only rendering optimistic values for updated fields on the UI.

src/App.tsx
import { generateClient } from 'aws-amplify/data'
import type { Schema } from '../amplify/data/resource'
import { useQueryClient, useMutation } from "@tanstack/react-query";
const client = generateClient<Schema>()
function App() {
const queryClient = useQueryClient();
const updateMutation = useMutation({
mutationFn: async (realEstatePropertyDetails: { id: string, name?: string, address?: string }) => {
const { data: updatedProperty } = await client.models.RealEstateProperty.update(realEstatePropertyDetails);
return updatedProperty;
},
// When mutate is called:
onMutate: async (newRealEstateProperty: { id: string, name?: string, address?: string }) => {
// Cancel any outgoing refetches
// (so they don't overwrite our optimistic update)
await queryClient.cancelQueries({
queryKey: ["realEstateProperties", newRealEstateProperty.id],
});
await queryClient.cancelQueries({
queryKey: ["realEstateProperties"],
});
// Snapshot the previous value
const previousRealEstateProperty = queryClient.getQueryData([
"realEstateProperties",
newRealEstateProperty.id,
]);
// Optimistically update to the new value
if (previousRealEstateProperty) {
queryClient.setQueryData(
["realEstateProperties", newRealEstateProperty.id],
/**
* `newRealEstateProperty` will at first only include updated values for
* the record. To avoid only rendering optimistic values for updated
* fields on the UI, include the previous values for all fields:
*/
{ ...previousRealEstateProperty, ...newRealEstateProperty }
);
}
// Return a context with the previous and new realEstateProperty
return { previousRealEstateProperty, newRealEstateProperty };
},
// If the mutation fails, use the context we returned above
onError: (err, newRealEstateProperty, context) => {
console.error("Error updating record:", err, newRealEstateProperty);
if (context?.previousRealEstateProperty) {
queryClient.setQueryData(
["realEstateProperties", context.newRealEstateProperty.id],
context.previousRealEstateProperty
);
}
},
// Always refetch after error or success:
onSettled: (newRealEstateProperty) => {
if (newRealEstateProperty) {
queryClient.invalidateQueries({
queryKey: ["realEstateProperties", newRealEstateProperty.id],
});
queryClient.invalidateQueries({
queryKey: ["realEstateProperties"],
});
}
},
});
}

Optimistically render deleting a record

To optimistically render a deletion of a single record, use the TanStack useMutation hook, passing in the delete mutation as the mutationFn parameter. We'll use the same query key combination used by the single record useQuery hook (realEstateProperties and the record's id) as the query key to optimistically render the updates. We'll use the onMutate function to update the cache directly, as well as the onError function to rollback changes when a delete fails.

src/App.tsx
import { generateClient } from 'aws-amplify/data'
import type { Schema } from '../amplify/data/resource'
import { useQueryClient, useMutation } from '@tanstack/react-query'
const client = generateClient<Schema>()
function App() {
const queryClient = useQueryClient();
const deleteMutation = useMutation({
mutationFn: async (realEstatePropertyDetails: { id: string }) => {
const { data: deletedProperty } = await client.models.RealEstateProperty.delete(realEstatePropertyDetails);
return deletedProperty;
},
// When mutate is called:
onMutate: async (newRealEstateProperty) => {
// Cancel any outgoing refetches
// (so they don't overwrite our optimistic update)
await queryClient.cancelQueries({
queryKey: ["realEstateProperties", newRealEstateProperty.id],
});
await queryClient.cancelQueries({
queryKey: ["realEstateProperties"],
});
// Snapshot the previous value
const previousRealEstateProperty = queryClient.getQueryData([
"realEstateProperties",
newRealEstateProperty.id,
]);
// Optimistically update to the new value
if (previousRealEstateProperty) {
queryClient.setQueryData(
["realEstateProperties", newRealEstateProperty.id],
newRealEstateProperty
);
}
// Return a context with the previous and new realEstateProperty
return { previousRealEstateProperty, newRealEstateProperty };
},
// If the mutation fails, use the context we returned above
onError: (err, newRealEstateProperty, context) => {
console.error("Error deleting record:", err, newRealEstateProperty);
if (context?.previousRealEstateProperty) {
queryClient.setQueryData(
["realEstateProperties", context.newRealEstateProperty.id],
context.previousRealEstateProperty
);
}
},
// Always refetch after error or success:
onSettled: (newRealEstateProperty) => {
if (newRealEstateProperty) {
queryClient.invalidateQueries({
queryKey: ["realEstateProperties", newRealEstateProperty.id],
});
queryClient.invalidateQueries({
queryKey: ["realEstateProperties"],
});
}
},
});
}

Loading and error states for optimistically rendered data

Both useQuery and useMutation return isLoading and isError states that indicate the current state of the query or mutation. You can use these states to render loading and error indicators.

In addition to operation-specific loading states, TanStack Query provides a useIsFetching hook. For the purposes of this demo, we show a global loading indicator in the Complete Example when any queries are fetching (including in the background) in order to help visualize what TanStack is doing in the background:

function GlobalLoadingIndicator() {
const isFetching = useIsFetching();
return isFetching ? <div style={styles.globalLoadingIndicator}></div> : null;
}

For more details on advanced usage of TanStack Query hooks, see the TanStack documentation.

The following example demonstrates how to use the state returned by TanStack to render a loading indicator while a mutation is in progress, and an error message if the mutation fails. For additional examples, see the Complete Example below.

<>
{updateMutation.isError &&
updateMutation.error instanceof Error ? (
<div>An error occurred: {updateMutation.error.message}</div>
) : null}
{updateMutation.isSuccess ? (
<div>Real Estate Property updated!</div>
) : null}
<button
onClick={() =>
updateMutation.mutate({
id: realEstateProperty.id,
address: `${Math.floor(
1000 + Math.random() * 9000
)} Main St`,
})
}
>
Update Address
</button>
</>

Complete example

src/main.tsx
import React from 'react'
import ReactDOM from 'react-dom/client'
import App from './App.tsx'
import './index.css'
import { Amplify } from 'aws-amplify'
import outputs from '../amplify_outputs.json'
import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
import { ReactQueryDevtools } from "@tanstack/react-query-devtools";
Amplify.configure(outputs)
export const queryClient = new QueryClient()
ReactDOM.createRoot(document.getElementById('root')!).render(
<React.StrictMode>
<QueryClientProvider client={queryClient}>
<App />
<ReactQueryDevtools initialIsOpen={false} />
</QueryClientProvider>
</React.StrictMode>,
)
src/App.tsx
import { generateClient } from 'aws-amplify/data'
import type { Schema } from '../amplify/data/resource'
import './App.css'
import { useIsFetching, useMutation, useQuery } from '@tanstack/react-query'
import { queryClient } from './main'
import { useState } from 'react'
const client = generateClient<Schema>({
authMode: 'iam'
})
function GlobalLoadingIndicator() {
const isFetching = useIsFetching();
return isFetching ? <div style={styles.globalLoadingIndicator}></div> : null;
}
function App() {
const [currentRealEstatePropertyId, setCurrentRealEstatePropertyId] =
useState<string | null>(null);
const {
data: realEstateProperties,
isLoading,
isSuccess,
isError: isErrorQuery,
} = useQuery({
queryKey: ["realEstateProperties"],
queryFn: async () => {
const response = await client.models.RealEstateProperty.list();
const allRealEstateProperties = response.data;
if (!allRealEstateProperties) return null;
return allRealEstateProperties;
},
});
const createMutation = useMutation({
mutationFn: async (input: { name: string, address: string }) => {
const { data: newRealEstateProperty } = await client.models.RealEstateProperty.create(input)
return newRealEstateProperty;
},
// When mutate is called:
onMutate: async (newRealEstateProperty) => {
// Cancel any outgoing refetches
// (so they don't overwrite our optimistic update)
await queryClient.cancelQueries({ queryKey: ["realEstateProperties"] });
// Snapshot the previous value
const previousRealEstateProperties = queryClient.getQueryData([
"realEstateProperties",
]);
// Optimistically update to the new value
if (previousRealEstateProperties) {
queryClient.setQueryData(["realEstateProperties"], (old: Schema["RealEstateProperty"]["type"][]) => [
...old,
newRealEstateProperty,
]);
}
// Return a context object with the snapshotted value
return { previousRealEstateProperties };
},
// If the mutation fails,
// use the context returned from onMutate to rollback
onError: (err, newRealEstateProperty, context) => {
console.error("Error saving record:", err, newRealEstateProperty);
if (context?.previousRealEstateProperties) {
queryClient.setQueryData(
["realEstateProperties"],
context.previousRealEstateProperties
);
}
},
// Always refetch after error or success:
onSettled: () => {
queryClient.invalidateQueries({ queryKey: ["realEstateProperties"] });
},
});
function RealEstatePropertyDetailView() {
const {
data: realEstateProperty,
isLoading,
isSuccess,
isError: isErrorQuery,
} = useQuery({
queryKey: ["realEstateProperties", currentRealEstatePropertyId],
queryFn: async () => {
if (!currentRealEstatePropertyId) { return }
const { data: property } = await client.models.RealEstateProperty.get({ id: currentRealEstatePropertyId });
return property
},
});
const updateMutation = useMutation({
mutationFn: async (realEstatePropertyDetails: { id: string, name?: string, address?: string }) => {
const { data: updatedProperty } = await client.models.RealEstateProperty.update(realEstatePropertyDetails);
return updatedProperty;
},
// When mutate is called:
onMutate: async (newRealEstateProperty: { id: string, name?: string, address?: string }) => {
// Cancel any outgoing refetches
// (so they don't overwrite our optimistic update)
await queryClient.cancelQueries({
queryKey: ["realEstateProperties", newRealEstateProperty.id],
});
await queryClient.cancelQueries({
queryKey: ["realEstateProperties"],
});
// Snapshot the previous value
const previousRealEstateProperty = queryClient.getQueryData([
"realEstateProperties",
newRealEstateProperty.id,
]);
// Optimistically update to the new value
if (previousRealEstateProperty) {
queryClient.setQueryData(
["realEstateProperties", newRealEstateProperty.id],
/**
* `newRealEstateProperty` will at first only include updated values for
* the record. To avoid only rendering optimistic values for updated
* fields on the UI, include the previous values for all fields:
*/
{ ...previousRealEstateProperty, ...newRealEstateProperty }
);
}
// Return a context with the previous and new realEstateProperty
return { previousRealEstateProperty, newRealEstateProperty };
},
// If the mutation fails, use the context we returned above
onError: (err, newRealEstateProperty, context) => {
console.error("Error updating record:", err, newRealEstateProperty);
if (context?.previousRealEstateProperty) {
queryClient.setQueryData(
["realEstateProperties", context.newRealEstateProperty.id],
context.previousRealEstateProperty
);
}
},
// Always refetch after error or success:
onSettled: (newRealEstateProperty) => {
if (newRealEstateProperty) {
queryClient.invalidateQueries({
queryKey: ["realEstateProperties", newRealEstateProperty.id],
});
queryClient.invalidateQueries({
queryKey: ["realEstateProperties"],
});
}
},
});
const deleteMutation = useMutation({
mutationFn: async (realEstatePropertyDetails: { id: string }) => {
const { data: deletedProperty } = await client.models.RealEstateProperty.delete(realEstatePropertyDetails);
return deletedProperty;
},
// When mutate is called:
onMutate: async (newRealEstateProperty) => {
// Cancel any outgoing refetches
// (so they don't overwrite our optimistic update)
await queryClient.cancelQueries({
queryKey: ["realEstateProperties", newRealEstateProperty.id],
});
await queryClient.cancelQueries({
queryKey: ["realEstateProperties"],
});
// Snapshot the previous value
const previousRealEstateProperty = queryClient.getQueryData([
"realEstateProperties",
newRealEstateProperty.id,
]);
// Optimistically update to the new value
if (previousRealEstateProperty) {
queryClient.setQueryData(
["realEstateProperties", newRealEstateProperty.id],
newRealEstateProperty
);
}
// Return a context with the previous and new realEstateProperty
return { previousRealEstateProperty, newRealEstateProperty };
},
// If the mutation fails, use the context we returned above
onError: (err, newRealEstateProperty, context) => {
console.error("Error deleting record:", err, newRealEstateProperty);
if (context?.previousRealEstateProperty) {
queryClient.setQueryData(
["realEstateProperties", context.newRealEstateProperty.id],
context.previousRealEstateProperty
);
}
},
// Always refetch after error or success:
onSettled: (newRealEstateProperty) => {
if (newRealEstateProperty) {
queryClient.invalidateQueries({
queryKey: ["realEstateProperties", newRealEstateProperty.id],
});
queryClient.invalidateQueries({
queryKey: ["realEstateProperties"],
});
}
},
});
return (
<div style={styles.detailViewContainer}>
<h2>Real Estate Property Detail View</h2>
{isErrorQuery && <div>{"Problem loading Real Estate Property"}</div>}
{isLoading && (
<div style={styles.loadingIndicator}>
{"Loading Real Estate Property..."}
</div>
)}
{isSuccess && (
<div>
<p>{`Name: ${realEstateProperty?.name}`}</p>
<p>{`Address: ${realEstateProperty?.address}`}</p>
</div>
)}
{realEstateProperty && (
<div>
<div>
{updateMutation.isPending ? (
"Updating Real Estate Property..."
) : (
<>
{updateMutation.isError &&
updateMutation.error instanceof Error ? (
<div>An error occurred: {updateMutation.error.message}</div>
) : null}
{updateMutation.isSuccess ? (
<div>Real Estate Property updated!</div>
) : null}
<button
onClick={() =>
updateMutation.mutate({
id: realEstateProperty.id,
name: `Updated Home ${Date.now()}`,
})
}
>
Update Name
</button>
<button
onClick={() =>
updateMutation.mutate({
id: realEstateProperty.id,
address: `${Math.floor(
1000 + Math.random() * 9000
)} Main St`,
})
}
>
Update Address
</button>
</>
)}
</div>
<div>
{deleteMutation.isPending ? (
"Deleting Real Estate Property..."
) : (
<>
{deleteMutation.isError &&
deleteMutation.error instanceof Error ? (
<div>An error occurred: {deleteMutation.error.message}</div>
) : null}
{deleteMutation.isSuccess ? (
<div>Real Estate Property deleted!</div>
) : null}
<button
onClick={() =>
deleteMutation.mutate({
id: realEstateProperty.id,
})
}
>
Delete
</button>
</>
)}
</div>
</div>
)}
<button onClick={() => setCurrentRealEstatePropertyId(null)}>
Back
</button>
</div>
);
}
return (
<div>
{!currentRealEstatePropertyId && (
<div style={styles.appContainer}>
<h1>Real Estate Properties:</h1>
<div>
{createMutation.isPending ? (
"Adding Real Estate Property..."
) : (
<>
{createMutation.isError &&
createMutation.error instanceof Error ? (
<div>An error occurred: {createMutation.error.message}</div>
) : null}
{createMutation.isSuccess ? (
<div>Real Estate Property added!</div>
) : null}
<button
onClick={() => {
createMutation.mutate({
name: `New Home ${Date.now()}`,
address: `${Math.floor(
1000 + Math.random() * 9000
)} Main St`,
});
}}
>
Add RealEstateProperty
</button>
</>
)}
</div>
<ul style={styles.propertiesList}>
{isLoading && (
<div style={styles.loadingIndicator}>
{"Loading Real Estate Properties..."}
</div>
)}
{isErrorQuery && (
<div>{"Problem loading Real Estate Properties"}</div>
)}
{isSuccess &&
realEstateProperties?.map((realEstateProperty, idx) => {
if (!realEstateProperty) return null;
return (
<li
style={styles.listItem}
key={`${idx}-${realEstateProperty.id}`}
>
<p>{realEstateProperty.name}</p>
<button
style={styles.detailViewButton}
onClick={() =>
setCurrentRealEstatePropertyId(realEstateProperty.id)
}
>
Detail View
</button>
</li>
);
})}
</ul>
</div>
)}
{currentRealEstatePropertyId && <RealEstatePropertyDetailView />}
<GlobalLoadingIndicator />
</div>
);
}
export default App
const styles = {
appContainer: {
display: "flex",
flexDirection: "column",
alignItems: "center",
},
detailViewButton: { marginLeft: "1rem" },
detailViewContainer: { border: "1px solid black", padding: "3rem" },
globalLoadingIndicator: {
position: "fixed",
top: 0,
left: 0,
width: "100%",
height: "100%",
border: "4px solid blue",
pointerEvents: "none",
},
listItem: {
display: "flex",
justifyContent: "space-between",
border: "1px dotted grey",
padding: ".5rem",
margin: ".1rem",
},
loadingIndicator: {
border: "1px solid black",
padding: "1rem",
margin: "1rem",
},
propertiesList: {
display: "flex",
flexDirection: "column",
alignItems: "center",
justifyContent: "start",
width: "50%",
border: "1px solid black",
padding: "1rem",
listStyleType: "none",
},
} as const;