ItemFailed

Event v120 → current #4

Emitted for each call in a batch that failed.

View events on chain
Useful for: developersanalytics

The Big Picture

Contains the error from the failed call.

Use Cases

  • Debug individual batch call failures

From Chain Metadata

A single item within a Batch of dispatches has completed with error.

Triggers

Emitted by

force_batch

Preconditions

  • Part of force_batch
  • This call failed

Effects

Postconditions

  • Failed call had no effect

Event Data

#NameTypeDescription
0
error
DispatchError Error from the failed call

Code Examples

import { ApiPromise, WsProvider } from "@polkadot/api";
import { stringCamelCase } from "@polkadot/util";

const provider = new WsProvider("wss://entrypoint-finney.opentensor.ai:443");
const api = await ApiPromise.create({ provider });

// Subscribe to ItemFailed events
api.query.system.events((events) => {
  events
    .filter(({ event }) =>
      event.section === stringCamelCase("Utility") &&
      event.method === "ItemFailed"
    )
    .forEach(({ event }) => {
      console.log("ItemFailed:", event.data.toHuman());
    });
});

On-Chain Activity

Emission Frequency
●●●●○○ Significant 1M–5M emissions

Major features with millions of emissions

#22 most emitted event

As of block 7,429,232

Runtime Info

Pallet Index
11
Event Index
4
First Version
v120
Current Version
v393
Back to Utility Events