[Ethereum] How to ethers.js using infura as provider

This is something I was also wondering recently when I was getting 429 Too Many Requests responses from the default provider. Looking at the source code there are default API keys hardcoded in the source code (see etherscan-provider.ts#L87 and infura-provider.ts#17).

It is possible that Richard has some additional arrangements with Etherscan/Infura to allow higher rate limits on those keys, but as I noticed, it is possible to hit the rate limits.

In order to know whether a transaction (transactionHash) has been mined and confirmed, the following steps are required:

1. Get the transaction receipt
2. Check whether the transaction has been included in a block i.e. the blockNumber is not null

Below is the code snippet for achieving this:

const isTransactionMined = async(transactionHash) => {
    const txReceipt = await provider.getTransactionReceipt(transactionHash);
    if (txReceipt && txReceipt.blockNumber) {
        return txReceipt;
    }
}

In this way you can check whether the transaction has been mined.