update (#559)

Author: aditya520

pages/price-feeds/use-real-time-data/off-chain.mdx

@@ -1,116 +1,13 @@
-# How to Use Real-Time Data in Off-Chain Applications
-
-This guide explains how to use the [typescript SDK client](https://github.com/pyth-network/pyth-crosschain/tree/main/price_service/client/js) to fetch the latest prices and subscribe to real-time price updates in off-chain applications.
-
-## Installation
-
-The Pyth SDK can be installed using npm or yarn:
-
-### npm
-
-```bash copy
-npm install --save @pythnetwork/price-service-client
-```
-
-### Yarn
-
-```bash copy
-yarn add @pythnetwork/price-service-client
-```
-
-## Usage
-
-Typical usage of the Pyth SDK involves creating a `PriceServiceConnection` instance, by passing the URL of the [Hermes](https://hermes.pyth.network/docs/#/) service to the constructor.
-You can then use the `getLatestPriceFeeds` method to fetch the latest prices of the specified price feeds:
-
-```typescript copy
-// Get the Stable Hermes service URL from https://docs.pyth.network/price-feeds/api-instances-and-providers/hermes
-const connection = new PriceServiceConnection("https://hermes.pyth.network");
-
-const priceIds = [
-  "0xe62df6c8b4a85fe1a67db44dc12de5db330f7ac66b72dc658afedf0f4a415b43", // BTC/USD price id
-  "0xff61491a931112ddf1bd8147cd1b641375f79f5825126d665480874634fd0ace", // ETH/USD price id
-];
+import { Callout } from "nextra/components";
 
-// Get the latest values of the price feeds as JSON objects.
-const currentPrices = await connection.getLatestPriceFeeds(priceIds);
-console.log(currentPrices);
-```
-
-The `getLatestPriceFeeds` method returns an array of `PriceFeed` objects. Each `PriceFeed` object contains the latest price, the Exponential Moving Average (EMA) price, and other metadata:
-
-```bash
-[
-  PriceFeed {
-    emaPrice: Price {
-      conf: '3450227100',
-      expo: -8,
-      price: '6610104500000',
-      publishTime: 1715870606
-    },
-    id: 'e62df6c8b4a85fe1a67db44dc12de5db330f7ac66b72dc658afedf0f4a415b43',
-    metadata: undefined,
-    vaa: undefined,
-    price: Price {
-      conf: '3315255511',
-      expo: -8,
-      price: '6619626406527',
-      publishTime: 1715870606
-    }
-  },
-  PriceFeed {
-    emaPrice: Price {
-      conf: '266713535',
-      expo: -8,
-      price: '297876550000',
-      publishTime: 1715870606
-    },
-    id: 'ff61491a931112ddf1bd8147cd1b641375f79f5825126d665480874634fd0ace',
-    metadata: undefined,
-    vaa: undefined,
-    price: Price {
-      conf: '296893358',
-      expo: -8,
-      price: '296499502000',
-      publishTime: 1715870606
-    }
-  }
-]
-```
-
-You can also subscribe to real-time price updates over a WebSocket connection using the `subscribePriceFeedUpdates` method:
-
-```typescript copy
-// priceIds here is the one declared in the above code snippet.
-const priceFeeds = await connection.getLatestPriceFeeds(priceIds);
-
-connection.subscribePriceFeedUpdates(priceIds, (priceFeed) => {
-  // priceFeed here is the same as returned by getLatestPriceFeeds above.
-  console.log(
-    `Received an update for ${priceFeed.id}: ${priceFeed.getPriceNoOlderThan(
-      60
-    )}`
-  );
-});
-
-// When using the subscription, make sure to close the WebSocket upon termination to finish the process gracefully.
-setTimeout(() => {
-  connection.closeWebSocket();
-}, 60000);
-```
-
-## Additional Resources
-
-You may find these additional resources helpful.
-
-### Examples
-
-This [example](https://github.com/pyth-network/pyth-crosschain/blob/main/price_service/client/js/src/examples/PriceServiceClient.ts) demonstrates how to use the Pyth SDK to fetch prices.
+# How to Use Real-Time Data in Off-Chain Applications
 
-### Hermes API Reference
+This guide explains how to fetch the latest prices and subscribe to real-time price updates in off-chain applications.
 
-The [Hermes API](https://hermes.pyth.network/docs/#/) reference lets you interactively explore the complete API of the Pyth Hermes service.
+<Callout type="info" emoji="💡">
+  [`price-service-sdk`](https://github.com/pyth-network/pyth-crosschain/tree/main/price_service/client/js) was is deprecated and replaced by the [`hermes-client`](https://github.com/pyth-network/pyth-crosschain/tree/main/apps/hermes/client/js).
+  It can be used for fetching prices for off-chain applications as well as fetching price updates.
 
-### Price Feed IDs
+Please refer to the [fetch-price-updates](../fetch-price-updates) guide for the details.
 
-The [Price Feed IDs](https://pyth.network/developers/price-feed-ids) lists the price feeds available on the Pyth network.
+</Callout>