paramsEncodingDecoding.ts

import { Bytes, Raw } from "@polkadot/types";

import { ChannelMetadata } from "@joystream/content-metadata-protobuf";
import { ChannelCreationParameters } from "@joystream/types/content";

// getApi, getAssets, getRewardAccount and getMetaFromEvent are stubs here

const api = await getApi();


// ===== encode channel params =====

const metadata = new ChannelMetadata();
metadata.setTitle("my new channel");

const serialized = metadata.serializeBinary();

// api.createType('Raw', serialized) can be used as well
const metaRaw = new Raw(api.registry, serialized);
const meta = new Bytes(api.registry, serializedRaw);

const params = new ChannelCreationParameters(api.registry, {
  meta,
  assets: getAssets(),
  reward_account: getRewardAccount(),
});


// ===== decode channel params =====

const metaBytes = getMetaFromEvent(); // meta will be of type Bytes

// true option here is crucial, it indicates that we want just the underlying bytes (by default it will also include bytes encoding the length)
const metaU8a = metaBytes.toU8a(true);

const decoded = ChannelMetadata.deserializeBinary(metaU8a);