read contract from specific blockstamp?

[dellwatson]

how to read contract functions from specific blockstamp? i did use connect and it's not working too on my react app

 const ContractLastMonth = Contract
      .connect(matic_provider)
      .at(lastMonthBlockNumber);
    const balanceLastMonthBlock = await ContractLastMonth.balanceOf(address);
    LIST_RESULT_LAST_MONTH.push({
      address: address,
      balance: balanceLastMonthBlock.toString(),
    });
    ```

[ricmoo]

To read from block height 1000, you'd use:

const balanceLastMonthBlock = await ContractLastMonth.balanceOf(address, { blockTag: 1000 });

But keep in mind this only works if your backend supports archive mode, and unfortunately if you have a non-archive node, it is silently ignored and "latest" is used. :(

[dellwatson]

i got error:
Error: invalid hexlify value [ See: https://links.ethers.org/v5-errors-NUMERIC_FAULT ] (operation="checkSafeInteger", fault="non-integer", value=41716960.384615384, code=NUMERIC_FAULT, version=bytes/5.7.0)

what is that mean?

im using simple block calc:

  const blocksPer24Hours = (24 * 60 * 60) / 13; // assuming an average block time of 13 seconds
  const last24HoursBlockNumber = currentBlockNumber - blocksPer24Hours;
  // Calculate the block numbers for the specified time periods
  const blocksPerMonth = (30 * 24 * 60 * 60) / 13; // assuming an average block time of 13 seconds
  const blocksPerSixMonths = blocksPerMonth * 6;

[zemse]

(30 * 24 * 60 * 60) / 13 Since this is not solidity, it's js, so you would get a floating point number. In order to get rid of the fractional part you need to Math.floor((30 * 24 * 60 * 60) / 13)

[ricmoo]

One small nitpick. :)

You should use Math.trunc, when trying to mimic integer maths (or just use ES2020 BigInt):

// Correct integer maths using BigInt
> 3n / 2n
1n
> -3n / 2n
-1n

// Notice the difference below; floor rounds down, trunk rounds towards 0

// Floor (Matches for positive values, but rounds the wrong way for negative values)
> Math.floor(3 / 2)
1
> Math.floor(-3 / 2)
-2

// Truncate (matches BigInt)
> Math.trunc(3 / 2)
1
> Math.trunc(-3 / 2)
-1

Yay numbers... :p

[dellwatson]

it works now, but im just using the rpc url https://polygon-rpc.com. does it mean this is rpc url is an archive node? @ricmoo