String Undefined Error

[dizzy222]

I am getting this error when trying to deploy the smart contract via truffle. Any ideas?

hardhat.config.ts:128:7 - error TS2322: Type 'string | undefined' is not assignable to type 'string'.
Type 'undefined' is not assignable to type 'string'.

128 rinkeby: process.env.BLOCK_EXPLORER_API_KEY,
~~~~~~~
hardhat.config.ts:129:7 - error TS2322: Type 'string | undefined' is not assignable to type 'string'.
Type 'undefined' is not assignable to type 'string'.

129 mainnet: process.env.BLOCK_EXPLORER_API_KEY,
~~~~~~~
hardhat.config.ts:132:7 - error TS2322: Type 'string | undefined' is not assignable to type 'string'.
Type 'undefined' is not assignable to type 'string'.

132 polygon: process.env.BLOCK_EXPLORER_API_KEY,
~~~~~~~
hardhat.config.ts:133:7 - error TS2322: Type 'string | undefined' is not assignable to type 'string'.
Type 'undefined' is not assignable to type 'string'.

133 polygonMumbai: process.env.BLOCK_EXPLORER_API_KEY,
~~~~~~~~~~~~~

error Command failed with exit code 1.

[liarco]

Hi @dizzy222,
I'm unable to reproduce this error, unless I run a yarn upgrade. If you upgrade the dependencies the project may brake because it has been written and tested with lower versions.

⚠️ Remember: if you make changes to the code (especially upgrading the dependencies) it's your responsibility to make sure that everything works as intended and that there are no incompatibilities with the new dependency tree (e.g. the contract supports v3.x of ERC721A, compatibility with v4.x has never been tested and we talked about it in this video) ⚠️

That said, this specific error can be fixed by simply changing your hardhat configuration like this:

// ...
  etherscan: {
    apiKey: {
      // Ethereum
      rinkeby: process.env.BLOCK_EXPLORER_API_KEY ?? '',
      mainnet: process.env.BLOCK_EXPLORER_API_KEY ?? '',

      // Polygon
      polygon: process.env.BLOCK_EXPLORER_API_KEY ?? '',
      polygonMumbai: process.env.BLOCK_EXPLORER_API_KEY ?? '',
    },
  },
// ...