Events

The Contract interface also have APIs to help you work with fully-typed contract events easily and smoothly.

Decode contract events from transaction events

import { ContractEvent } from 'dedot/contract';

// Initialize Contract instance
const contract = new Contract<FlipperContractApi>(client, flipperMetadata, contractAddress, { defaultCaller: ALICE });

// Extracting contract events from transaction events
const { events } = await contract.tx.flip()
    .signAndSend(ALICE)
    .untilFinalized();
  
const flippedEvent = contract.events.Flipped.find(events);
console.log('Old value', flippedEvent.data.old);
console.log('New value', flippedEvent.data.new);

// an array of Flipped event
const flippedEvents = contract.events.Flipped.filter(events);

// Get all contract events from current transactions
const contractEvents: ContractEvent[] = contract.decodeEvents(events);

// Another way to get the Flipper event
const flippedEvent2 = contractEvents.find(contract.events.Flipped.is);

Decode contract events from system events

// Extracting contract events from system events
await client.query.system.events((events) => {
  // fully-typed event
  const flippedEvent = contract.events.Flipped.find(events); // or filter, is
  
  // get all events of this contract from current block
  const contractEvents: ContractEvent[] = contract.decodeEvents(events);
})

Contract Event API

find

Find the first target event from the provided events.

const { events } = await contract.tx.flip({ ... })..untilFinalized();

const flippedEvent = contract.events.Flipped.find(events);

filter

Filter the target event from the provided events.

const flippedEvents = contract.events.Flipped.filter(events);