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hcs/updateTopic

How to call the API from an app

Then, depending on whether you're trying to connect to a metamask account or a non-metamask account, you can call the snap API in the following way:

const snapId = `npm:@hashgraph/hedera-wallet-snap`

const snapAPI = async () => {
  const externalAccountParams = {
    externalAccount: {
      accountIdOrEvmAddress: '0.0.12345',
      curve: 'ED25519'
    }
  }

  await window.ethereum.request({
    method: 'wallet_invokeSnap',
    params: {
      snapId,
      request: {
        method: 'hcs/updateTopic',
        params: {
          network: 'testnet',
          topicId: '0.0.4617270',
          memo?, // Optional param - type: string
          expirationTime?, // Optional param - type: number
          adminKey?, // Optional param - type: string
          submitKey?, // Optional param - type: string
          autoRenewPeriod?, // Optional param - type: number
          autoRenewAccount?, // Optional param - type: string
          /* 
            Uncomment the below line if you want to connect 
            to a non-metamask account
          */
          // ...externalAccountParams
        }
      }
    }
  })
}

If you pass in adminKey,you will need this same key to update the topic in the future.
If you pass in submitKey, it'll make the topic private which means you need to use this key to submit messages to this topic.

What the API does

Parses the arguments that were passed.
Returns the transaction receipt as response

An example response:

{
    "currentAccount": {
        "metamaskEvmAddress": "0x0b3628d1b838993b5fceec8b2a26502e7a8e5241",
        "externalEvmAddress": "",
        "hederaAccountId": "0.0.3581604",
        "hederaEvmAddress": "0xca53f9c93d30e0b7212d67901e5a24fb090d542b",
        "publicKey": "0x0206022cea4c6dd6d2e7263b8802253971de922f5380661d97cba82dee66f57ad6",
        "balance": {
            "hbars": 86.77980052,
            "timestamp": "Mon, 22 Jul 2024 18:00:45 GMT",
            "tokens": {
                "0.0.4279119": {
                    "balance": 50,
                    "decimals": 1,
                    "tokenId": "0.0.4279119",
                    "name": "NewTuum",
                    "symbol": "NEWTUUM",
                    "tokenType": "FUNGIBLE_COMMON",
                    "supplyType": "INFINITE",
                    "totalSupply": "50",
                    "maxSupply": "0"
                }
            }
        },
        "network": "testnet",
        "mirrorNodeUrl": "https://testnet.mirrornode.hedera.com"
    },
    "receipt": {
        "status": "SUCCESS",
        "accountId": "",
        "fileId": "",
        "contractId": "",
        "topicId": "",
        "tokenId": "",
        "scheduleId": "",
        "exchangeRate": {
            "hbars": 30000,
            "cents": 202259,
            "expirationTime": "Tue, 23 Jul 2024 19:00:00 GMT",
            "exchangeRateInCents": 6.741966666666666
        },
        "topicSequenceNumber": "0",
        "topicRunningHash": "",
        "totalSupply": "0",
        "scheduledTransactionId": "",
        "serials": [],
        "duplicates": [],
        "children": []
    }
}

Live Demo on CodePen

hcs/updateTopic

How to call the API from an app

Hedera Wallet Snap connects to your currently connected Metamask account by default. To learn how apps can connect to Hedera Wallet Snap using a non-metamask(external) account, refer to this .

Then, depending on whether you're trying to connect to a metamask account or a non-metamask account, you can call the snap API in the following way:

const snapId = `npm:@hashgraph/hedera-wallet-snap`

const snapAPI = async () => {
  const externalAccountParams = {
    externalAccount: {
      accountIdOrEvmAddress: '0.0.12345',
      curve: 'ED25519'
    }
  }

  await window.ethereum.request({
    method: 'wallet_invokeSnap',
    params: {
      snapId,
      request: {
        method: 'hcs/updateTopic',
        params: {
          network: 'testnet',
          topicId: '0.0.4617270',
          memo?, // Optional param - type: string
          expirationTime?, // Optional param - type: number
          adminKey?, // Optional param - type: string
          submitKey?, // Optional param - type: string
          autoRenewPeriod?, // Optional param - type: number
          autoRenewAccount?, // Optional param - type: string
          /* 
            Uncomment the below line if you want to connect 
            to a non-metamask account
          */
          // ...externalAccountParams
        }
      }
    }
  })
}

If you pass in adminKey,you will need this same key to update the topic in the future.
If you pass in submitKey, it'll make the topic private which means you need to use this key to submit messages to this topic.

What the API does

Retrieves the currently connected account the user has selected on Metamask. If it's the first time, a new is created and the account info is saved in snap state.
Parses the arguments that were passed.
Calls the to update the properties of an existing topic such as memo, admin key, submit key, etc.
Returns the transaction receipt as response

An example response:

{
    "currentAccount": {
        "metamaskEvmAddress": "0x0b3628d1b838993b5fceec8b2a26502e7a8e5241",
        "externalEvmAddress": "",
        "hederaAccountId": "0.0.3581604",
        "hederaEvmAddress": "0xca53f9c93d30e0b7212d67901e5a24fb090d542b",
        "publicKey": "0x0206022cea4c6dd6d2e7263b8802253971de922f5380661d97cba82dee66f57ad6",
        "balance": {
            "hbars": 86.77980052,
            "timestamp": "Mon, 22 Jul 2024 18:00:45 GMT",
            "tokens": {
                "0.0.4279119": {
                    "balance": 50,
                    "decimals": 1,
                    "tokenId": "0.0.4279119",
                    "name": "NewTuum",
                    "symbol": "NEWTUUM",
                    "tokenType": "FUNGIBLE_COMMON",
                    "supplyType": "INFINITE",
                    "totalSupply": "50",
                    "maxSupply": "0"
                }
            }
        },
        "network": "testnet",
        "mirrorNodeUrl": "https://testnet.mirrornode.hedera.com"
    },
    "receipt": {
        "status": "SUCCESS",
        "accountId": "",
        "fileId": "",
        "contractId": "",
        "topicId": "",
        "tokenId": "",
        "scheduleId": "",
        "exchangeRate": {
            "hbars": 30000,
            "cents": 202259,
            "expirationTime": "Tue, 23 Jul 2024 19:00:00 GMT",
            "exchangeRateInCents": 6.741966666666666
        },
        "topicSequenceNumber": "0",
        "topicRunningHash": "",
        "totalSupply": "0",
        "scheduledTransactionId": "",
        "serials": [],
        "duplicates": [],
        "children": []
    }
}

Live Demo on CodePen

Note: Visit to activate your hedera account before you interact with the demo
If you're getting any errors with the live demo, make sure you go through the section to learn about what you may be missing. You need to install in your browser for the live demo to work.
To ease the integration of Hedera Wallet Snap on an application, we have created a template web application that you can run locally and check out the code in its entirety to learn how you can integrate and interact with various APIs exposed by Hedera Wallet Snap. Check out the full source code at .
You can also check out the to learn how each API works.