Metamask Error: TypeError: this._deployData.startsWith is not a function
When deploying a smart contract, you can use Web3.js to interact with the Ethereum network and store the collected data in two separate files according to your requirements. However, when using Metamask, an error occurs that seems to be related to calling the startsWith method of the _deployData object on its own instance.
To fix this issue, let’s see what could be causing it and how to resolve it.
Understanding the error
The error “TypeError: this._deployData.startsWith is not a function” occurs when Metamask tries to call the “startsWith” method on an object that does not support it. In your case, _deployData appears to be the property _deployed_data of the Web3 contract object, which is returned by the get deployed() method.
Possible Causes
- Incorrect ABI: Your compiled contract may not be properly included in the “abi.json” file located in your project’s “contracts” directory.
- Missing or incorrect data store: You are trying to save data from a separate file, but you have not configured Metamask to use this store.
- Network connectivity issues
: There may be connectivity issues with your network, which is causing the data hosted in the contract to not be saved correctly.
Solutions
1. Check the ABI
Make sure you have included all the required data in the abi.json file:
{
"Contract Name": "",
"ABIVersion": "",
// ... other properties ...
}
If your ABI version is incorrect or missing, update the “abi.json” file accordingly.
2. Set up a data store
Make sure you are using Metamask to store data from a separate file:
- Create a new contract: Compile and deploy the smart contract using Web3.js.
- Use the get deployed() method: Call this method on the Web3 contract object to retrieve its deployed state.
const web3 = require('web3');
const Contract = require('./Contract');
// Assuming the contract instance is “contract”.
async function main() {
const deployedData = await web3.eth.getDeployedState(contract.address);
console.log(deployedData);
// You can now use this data to deploy your new contract
}
3. Check your network connection
Check your network for connectivity issues:
- Metamask Settings
: Make sure metamask is set up correctly and has permission to access the blockchain.
- Network Connection: Try connecting to another node or testnet to rule out local connectivity issues.
Use Case Example
Let’s say you have your contract built like this:
{
"ContractName": "MySmartContract",
"ABIVersion": "1",
"bytecode": "0x1234567890abcdef"
}
You can use the “get deployed()” method to retrieve the deployment state of your contract:
const web3 = require('web3');
const Contract = require('./MySmartContract');
async function main() {
const deployedData = await web3.eth.getDeployedState(Contract.address);
console.log(deployedData);
// You can now use this data to deploy your new contract
}
If the “get deployed()” method returns an empty object, it may indicate that Metamask is not storing the data correctly.
By following these steps and troubleshooting strategies, you should be able to resolve the error and successfully deploy your smart contract using Metamask.