fic(docs): use getFeedByIdInWei properly

Author: swarna1101

docs/ftso/2-feeds.mdx

@@ -32,7 +32,7 @@ The resulting string is then prefixed with `0x`.
 - Feed IDs are **not** addresses. They are `bytes21` structured encodings that combine the category and feed name to ensure each feed has a unique identifier.
 - **Do not** hardcode the number of decimals for a feed in your smart contract, as these can change as the feed value changes. You can use either of the following solutions:
   - Check the number of decimal places every query ([`getFeedById`](/ftso/solidity-reference/FtsoV2Interface#getfeedbyid)).
-  - Use the feed value in Wei ([`getFeedsByIdInWei`](/ftso/solidity-reference/FtsoV2Interface#getfeedsbyidinwei)).
+  - Use the feed value in Wei ([`getFeedByIdInWei`](/ftso/solidity-reference/FtsoV2Interface#getfeedbyidinwei)).
 
 :::
 

docs/ftso/solidity-reference/FtsoV2Interface.md

@@ -8,6 +8,7 @@ import Remix from "@site/src/components/remix";
 import CodeBlock from "@theme/CodeBlock";
 import FTSOV2FeedById from "!!raw-loader!/examples/developer-hub-solidity/FTSOV2FeedById.sol";
 import FTSOV2FeedByIndex from "!!raw-loader!/examples/developer-hub-solidity/FTSOV2FeedByIndex.sol";
+import FTSOV2FeedByIdWei from "!!raw-loader!/examples/developer-hub-solidity/FTSOV2FeedByIdWei.sol";
 import FTSOV2FeedsById from "!!raw-loader!/examples/developer-hub-solidity/FTSOV2FeedsById.sol";
 import FTSOV2FeedsByIdWei from "!!raw-loader!/examples/developer-hub-solidity/FTSOV2FeedsByIdWei.sol";
 import FTSOV2FeedsByIndexWei from "!!raw-loader!/examples/developer-hub-solidity/FTSOV2FeedsByIndexWei.sol";
@@ -56,6 +57,41 @@ function getFeedById(
 <Remix fileName="FTSOV2FeedById.sol">Open sample in Remix</Remix>
 <br></br>
 
+### getFeedByIdInWei
+
+Returns value in wei and timestamp of a feed.
+A fee (calculated by the FeeCalculator contract) may need to be paid.
+
+```solidity
+function getFeedByIdInWei(
+    bytes21 _feedId
+) external payable returns (
+    uint256 _value,
+    uint64 _timestamp
+);
+```
+
+#### Parameters
+
+- `_feedId`: The id of the feed.
+
+#### Returns
+
+- `_value`: The value for the requested feed in wei (i.e. with 18 decimal places).
+- `_timestamp`: The timestamp of the last update.
+
+<details>
+<summary>Sample contract usage</summary>
+
+<CodeBlock language="solidity" title="FTSOV2FeedByIdWei.sol">
+  {FTSOV2FeedByIdWei}
+</CodeBlock>
+
+</details>
+
+<Remix fileName="FTSOV2FeedByIdWei.sol">Open sample in Remix</Remix>
+<br></br>
+
 ### getFeedByIndex
 
 Returns stored data of a feed.

examples/developer-hub-solidity/FTSOV2FeedByIdWei.sol

@@ -11,58 +11,29 @@ import {TestFtsoV2Interface} from "@flarenetwork/flare-periphery-contracts/costo
  */
 contract FtsoV2FeedTracker {
     TestFtsoV2Interface internal ftsoV2;
-
-    // Feed data structure to store multiple feed values with timestamps
-    struct FeedInfo {
-        uint256 valueInWei;
-        uint64 timestamp;
-    }
-
-    // Mapping to store the latest feed data for a given index
-    mapping(uint256 => FeedInfo) public feedDataByIndex;
-    uint256 public highestValueIndex;
-    uint256 public highestValueInWei;
+    bytes21 public feedId =
+    bytes21(0x01464c522f55534400000000000000000000000000); // FLR/USD
 
     // Event to track feed retrieval
-    event FeedFetched(uint256 index, uint256 valueInWei, uint64 timestamp);
-
-    /**
-     * Constructor initializes the FTSOv2 contract.
-     * The contract registry is used to fetch the FtsoV2 contract address.
-     */
-    constructor() {
-        /* THIS IS A TEST METHOD, in production use: ftsoV2 = ContractRegistry.getFtsoV2(); */
-        ftsoV2 = ContractRegistry.getTestFtsoV2();
-    }
+    event FeedFetched(bytes21 feedId, uint256 valueInWei, uint64 timestamp);
 
     /**
      * Get the current value of a specific feed by its index, in wei.
-     * @param _index The index of the feed to retrieve.
      * @return _feedValue The latest price value of the feed in wei.
      * @return _timestamp The timestamp of the last update for the feed.
      */
-    function getFeedValueByIndexInWei(uint256 _index)
-        external
-        payable
-        returns (uint256 _feedValue, uint64 _timestamp)
+    function getFeedValueByIdWei()
+    external
+    payable
+    returns (uint256 _feedValue, uint64 _timestamp)
     {
+        /* THIS IS A TEST METHOD, in production use: ftsoV2 = ContractRegistry.getFtsoV2(); */
+        ftsoV2 = ContractRegistry.getTestFtsoV2();
         // Retrieve feed value and timestamp from the FtsoV2 contract
-        (_feedValue, _timestamp) = ftsoV2.getFeedByInWei{value: msg.value}(_index);
-
-        // Store the feed value and timestamp in the contract's storage
-        feedDataByIndex[_index] = FeedInfo({
-            valueInWei: _feedValue,
-            timestamp: _timestamp
-        });
-
-        // Update the highest value feed if applicable
-        if (_feedValue > highestValueInWei) {
-            highestValueInWei = _feedValue;
-            highestValueIndex = _index;
-        }
+        (_feedValue, _timestamp) = ftsoV2.getFeedByIdInWei(feedId);
 
         // Emit an event to log the feed retrieval
-        emit FeedFetched(_index, _feedValue, _timestamp);
+        emit FeedFetched(feedId, _feedValue, _timestamp);
     }
 
 }