revert transaction reason

revert_tx_reason.js

async function getRevertReason(txHash){

  const tx = await web3.eth.getTransaction(txHash)

  var result = await web3.eth.call(tx, tx.blockNumber)

  result = result.startsWith('0x') ? result : `0x${result}`

  if (result && result.substr(138)) {

    const reason = web3.utils.toAscii(result.substr(138))
    console.log('Revert reason:', reason)
    return reason

  } else {

    console.log('Cannot get reason - No return value')

  }

}