I'd like to get if the extrinsic completed without any extrinsic errors and get the errors if any. result.isError returns false when there's an error.

Could this be because I return DispatchResult instead of DispatchResultWithPostInfo in my pallet?

As this GitHub issue comment suggests, it can be done by getting the block details. But, I'm looking for a more simplified answer.

myTx.signAndSend(pair, (result) => {
    console.log(`Current status is ${result.status}`);

    console.log('has error', result.isError); // false

    if (result.isError) {
        console.log('dispatchError', result.dispatchError?.toHuman())
        console.log('internalError', result.internalError)

    if (result.status.isInBlock) {
        console.log(`Transaction included at blockHash ${result.status.asInBlock}`);
    } else if (result.status.isFinalized) {
        console.log(`Transaction finalized at blockHash ${result.status.asFinalized}`);

1 Answer 1


If there is a dispatchError then the transaction failed.

Have you tried something like this:

myTx.signAndSend(sender, ({ status, events, dispatchError }) => {
    // status would still be set, but in the case of error we can shortcut
    // to just check it (so an error would indicate InBlock or Finalized)
    if (dispatchError) {
      if (dispatchError.isModule) {
        // for module errors, we have the section indexed, lookup
        const decoded = api.registry.findMetaError(dispatchError.asModule);
        const { docs, name, section } = decoded;

        console.log(`${section}.${name}: ${docs.join(' ')}`);
      } else {
        // Other, CannotLookup, BadOrigin, no extra info

Reference: https://polkadot.js.org/docs/api/cookbook/tx#how-do-i-get-the-decoded-enum-for-an-extrinsicfailed-event

  • What is docs used for in RegistryError?
    – Burak
    Mar 4, 2022 at 0:25

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