List of upcoming breaking changes

[Nevon]

For many years now, we have never made a breaking change to KafkaJS (at least not intentionally), which is great for our users in the short term, but in the long term it also means we accumulate cruft and some slightly awkward APIs.

The intention of this issue is to collect all of the things that we have said we want to change in a single major version, so that when we feel that we have accumulated enough things we can actually put together a project to do them.

Planned breaking changes

• Remove ResourceTypes (Allow describe/alter config for broker configs #649)
• Remove topic argument from admin.fetchOffsets (New admin method for fetching group offsets for multiple topics #992)
• Remove admin.getTopicMetadata (Add admin#fetchTopicMetadata #331)
• Remove enforceRequestTimeout and enable by default (document enforceRequestTimeout #955)
• Remove TopicPartitionOffsetAndMedata type (Fix a typo in a type name #758)
• Remove support for Node 10
• Support duplicate header keys Feature/duplicate header keys #1132
• Remove originalError from errors (replaced by cause)
• Switch default partitioner to be Java compatible (Make JavaCompatiblePartitioner new default #1339)
• Remove deprecated topic argument from consumer.subscribe (Make consumer.subscribe accept an array of topics #1313)

Please leave a comment if you find more changes that should be on this list.

[ankon]

Remove typo-type:

kafkajs/types/index.d.ts

Lines 729 to 730 in addcd6f

	// TODO: Remove with 2.x
	export type TopicPartitionOffsetAndMedata = TopicPartitionOffsetAndMetadata

[t-d-d]

Switch default producer partitioner to JavaCompatiblePartitioner. #358

I realise that changing this has issues as it would cause problems for users that upgrade kafkajs version for their current apps. But as-is there are also issues when interacting with Java (or other) clients. We actually recently got bitten by this in production after moving to a new Kafka cluster where topics had been mirrored across via MirrorMaker (i.e. the Java producer.)

One option could be to not have a default partitioner but require one to be specified. Not a nice API but maybe it could be like that through the betas or for one dot version?

[Nevon]

Pushed a branch where I removed the topic: string argument from consumer.subscribe, which is replaced by topics: string[] but I'm waffling back and forth on whether or not it's a good change. The amount of complexity to support both is not that much, since we're pretty much just checking that we have one of the two arguments and then converting from string to string[] if needed. It does feel awkward to do consumer.subscribe({ topic: [topic] }), which might be the more common case. https://github.com/tulios/kafkajs/compare/remove-topic-from-subscribe?expand=1