existing example for blocktag?

[dellwatson]

I've tried override blocktag using infura and alchemy api, but none of them working.
Is there any example for this?

[zemse]

Blocktag would work if the node has archival access. Infura doesn't give archive access in free tier, need to take the pro version. For alchemy it'd work.

const balanceAtOldBlock = await tokenContract.balanceOf({
    blockTag: 100000,
});

Basically for a view/pure method, you can pass a blockTag override. Note that, for non-archive nodes (infura), the block tag is ignored.

[ricmoo]

Are you using blocktag or blockTag? The case is important. If you can include code examples it helps too.