Understanding Contract Method Call Return Types in web3.js 4

[BigBadAlien]

According to the documentation at https://docs.web3js.org/guides/smart_contracts/infer_contract_types/:

const balance = await contract.methods.balanceOf(holder).call();

The balanceOf method is typed, but the variable balance has the type MatchPrimitiveType<"uint8", unknown>. It doesn't throw an error in the case:

const balance: Date = await contract.methods.balanceOf(holder).call(); // Obviously it's not a `Date` but typescript doesn't throw an Error

This suggests that the return type isn’t strictly enforced. I suppose this might be due to formatters flexibility. Is the intended approach to always set the return type explicitly, like const balance: bigint?

[TatyOko28]

Yes, the return type from Web3.js v4 contract method calls is not strictly enforced due to the generic typing system.
✅ Best Practice: Always explicitly define the return type when handling Solidity contract calls in TypeScript, e.g.,

const balance: bigint = await contract.methods.balanceOf(holder).call();

This ensures type safety and prevents unintended errors.