How to get revert message in Web3js?

Question

I want to get the revert massage from a send method call to a smart contract. So I use: receipt.logs[0].data that is a string containing a hexadecimal value.

Now I want to to decode this value to get the revert message. So I use web3.eth.abi.decodeParameter method. The main problem is how to give type parameter to get the proper message.

For example If I give:

    const data = '0x0000000000000000000000000000000000000000000000000000c51ccda68b0000000000000000000000000000000000000000000000000002774a57aab99b34000000000000000000000000000000000000000000003692f60f63a91b794ce70000000000000000000000000000000000000000000000000276853add131034000000000000000000000000000000000000000000003692f61028c5e91fd7e7';
    window.web3 = new Web3('https://rpc-mumbai.maticvigil.com');
    window.ethereum.enable();
    web3.eth.handleRevert = true;
    let revertType = [{
        type: 'string', 
        name: 'message'
    }];
    const reason = web3.eth.abi.decodeParameter(revertType, data);
    console.log(reason);

It logs:

Uncaught (in promise) Error: invalid type (argument="type", value="messanger", code=INVALID_ARGUMENT, version=abi/5.7.0)

And if I use:

    const data = '0x0000000000000000000000000000000000000000000000000000c51ccda68b0000000000000000000000000000000000000000000000000002774a57aab99b34000000000000000000000000000000000000000000003692f60f63a91b794ce70000000000000000000000000000000000000000000000000276853add131034000000000000000000000000000000000000000000003692f61028c5e91fd7e7';
    window.web3 = new Web3('https://rpc-mumbai.maticvigil.com');
    window.ethereum.enable();
    web3.eth.handleRevert = true;
    const reason = web3.eth.abi.decodeParameter('string', data);
    console.log(reason);

It logs:

index.ts:269 Uncaught (in promise) Error: data out-of-bounds (length=0, offset=32, code=BUFFER_OVERRUN, version=abi/5.7.0)

The txHash in this example is 0x074e91fe5c1535d9bdc2bbc8cbadc0378c93eb06318401b1f341d844185430fb on Mumbai Polygon testnet: https://mumbai.polygonscan.com/tx/0x074e91fe5c1535d9bdc2bbc8cbadc0378c93eb06318401b1f341d844185430fb

Answer 1

There's a better way to do this in Web3.js.

---

// index.js
const { Web3 } = require("web3");

const rpcProvider = 'https://rpc.ankr.com/polygon_mumbai'; // 'https://polygon-testnet.public.blastapi.io';
const web3Provider = new Web3.providers.HttpProvider(rpcProvider);
const web3 = new Web3(web3Provider);


web3.eth.getBlockNumber().then((result) => {
    console.log("Latest Ethereum Block is: ", result); // confirm that the HTTP RPC provider has been instantiated properly
});

const txHash = '0x074e91fe5c1535d9bdc2bbc8cbadc0378c93eb06318401b1f341d844185430fb';

web3.eth.handleRevert = true;

web3.eth.getTransaction(txHash).then(async (tx) => {
    if (tx.gasPrice) {
        delete tx.maxPriorityFeePerGas;
        delete tx.maxFeePerGas;
    }
    try {
        let result = await web3.eth.call(tx, tx.blockNumber); // mock a call to reproduce the tx, otherwise it's hard to get the revert error from just the past tx hash'es logs
    }
    catch (err) {
        // the following transformations are necessary to remove the extra strings from the error object (the ones that mess up with the normal object type access)
        let errFlat = JSON.stringify(err);
        let { innerError : { message } } = JSON.parse(errFlat);

        message = message.replace('execution reverted: ', '');
        console.log(message);
    }
});

The output after node index.js will be:

Latest Ethereum Block is:  46569344n
You cannot buy this package again.

The approach is the following:

• Firstly, retrieve the original transaction (using the txHash)
• Next, you should mock an RPC call (it will not update anything in the blockchain state, and is just a helper utility)
• Finally then, catch the revert reason with the try { ... } catch (err) { ... } block

-> That way you get the revert error details, and eventually trim it to get the message thrown from the Solidity contract's code.

---

Here's the web (browser) version

const rpcProvider = 'https://rpc.ankr.com/polygon_mumbai';
const web3Provider = new Web3.providers.HttpProvider(rpcProvider);
const web3 = new Web3(web3Provider);


web3.eth.getBlockNumber().then((result) => {
    console.log("Latest Ethereum Block is: ", result); // confirm that the HTTP RPC provider has been instantiated properly
});

const txHash = '0x074e91fe5c1535d9bdc2bbc8cbadc0378c93eb06318401b1f341d844185430fb';

web3.eth.handleRevert = true;

web3.eth.getTransaction(txHash).then(async (tx) => {
    if (tx.gasPrice) {
        delete tx.maxPriorityFeePerGas;
        delete tx.maxFeePerGas;
    }
    try {
        let result = await web3.eth.call(tx, tx.blockNumber); // mock a call to reproduce the tx, otherwise it's hard to get the revert error from just the past tx hash'es logs

        console.log(result);
    }
    catch (err) {
        // the following transformations are necessary to remove the extra strings from the error object (the ones that mess up with the normal object type access)
        let errFlat = JSON.stringify(err);

        console.log(errFlat);

        const errParsed = JSON.parse(errFlat);

        message = errParsed.innerError ? errParsed.innerError?.message.replace('execution reverted: ', '') : errParsed.reason;
        console.log(message);
    }
});

The result is the following:

---

Conclusion:

• In the NodeJS (server) environment, you should reference errObject.innerError.message to get the transaction's revert message
• In the browser environment, just errObject.reason is sufficient :)

---

(Update) Taking a closer look, it's clear that the difference is due to that I used web3@ ^ 4.0.0 (4.5.0, to be specific), and Alireza has been using [email protected] via a CDN source. Hence the incompatible properties. https://docs.web3js.org/docs/guides/web3_migration_guide)

Therefore, the difference between the NodeJS and browser code snippet versions is that there's no difference if same versions are used across environments. 🙂