Detect best price (v3 or v2)

I am legitimately lost in the uniswap v3 documentation.
my ultimate goal is to understand if a token is v3 or v2 with typescript, or at least define the best price, if it is in v3 or v2.

I'm currently trying to get the example to work on this documentation page. But unlike what it should be it's not a ready-to-use example, several imports and comments are missing.
Even though I can complete the example I get the following error:
"The argument of type '{data: string; to: string; value: number; from: string; gasPrice: number;}' is not assignable to the parameter of type 'string | Promise <string>'

Start with the Uniswap SDK auto-router documentation page linked in the issue and reproduce the TypeScript error using its example. Review the missing imports, comments, and transaction-call typing; done means the example is complete and runs without the reported type error for the documented v2/v3 price flow.