chore: remove redundant SingleShardInfo type

[weboko]

This is a change request

Problem

Both ShardInfo and SingleShardInfo at the same time make experience confusing and prone to errors as they are not compatible with each other.

Proposed Solutions

Use only ShardInfo.

[danisharora099]

SingleShardInfo represents a combination of one shard and one clusterId, while ShardInfo represents multiple shards and one clusterId.

Taking an example of where SingleShardInfo is used, for example creating a decoder:
Providing multiple shards would map to multiple pubsub topics, which is against the design of creating one decoder: one decoder maps to one pubsub topic

If we deprecate SingleShardInfo and use ShardInfo, this would break the design of creating a decoder

[weboko]

This is a valid concern and I agree. We can keep SingleShardInfo as an alias.

Let's re-iterate:

SingleShardInfo -

js-waku/packages/interfaces/src/message.ts

Line 3 in 88e33a9

export interface SingleShardInfo {

ShardInfo -

js-waku/packages/interfaces/src/sharding.ts

Line 1 in 88e33a9

export type ShardInfo = {

Because they are not compatible - we have to use mapping function, it's easy to get confused and we got bugs in the past.

type SingleShardInfo = {
  clusterId: number;
  shards: [number];
};

wdyt, @danisharora099 ?