Review contract function response by block number

Question

I am looking way to create a report on how specific function responses change block by block.

Something like:

   const responses = []

   
   for(let i = 0; i < blockNumberList.length; i++){
     const blockNumber = blockNumberList[i]
     const response = await contract.foo() // <-- should return response by block number
     responses.push(response)
   } 

What I do now:

I have hardhat project with config like:

hardhat: {
  forking: {
    url: ''https://mainnet.infura.io/v3/key',
      blockNumber: 13413700,
    },
},

and function call like:

  const response = contract.func()

If I change manually blocknumber and restart harhad console, I get different responses by blocknumber.

I am looking more efficient way to collect responses than collect then manually changing config.

Answer 1

For view functions, ethers.js allow a blockTag override.

for(let i = 0; i < blockNumberList.length; i++){
  const blockNumber = blockNumberList[i]
  const response = await contract.foo({
    blockTag: blockNumber
  })
} 

For this, you need an archive node (I think you already have that arranged since you are using hardhat mainnet fork, but just mentioning here).

Some backends who are not archive nodes, they silently ignore the blockTag and give you state for latest block, you may have to watch out for that as well :P