Update to use level 8

[finwo]

Includes:

• Update dependencies #198
• level ^8.0.0 https://github.com/Level/level/blob/master/UPGRADING.md #196

Extras:

• Adds a polyfill for levelup.createValueStream (and related methods), as that has been ditched with level 8 using it's default classic-level export

[vweevers]

FYI for the streams, see https://github.com/Level/read-stream

[finwo]

FYI for the streams, see https://github.com/Level/read-stream

Awesome, I'll try to implement that tomorrow instead of the custom workaround

[finwo]

Just tried using level-read-stream, but I ran into the following error:

     Uncaught TypeError: db[method] is not a function
      at new LevelReadStream (node_modules/level-read-stream/index.js:17:33)
      at new ValueStream (node_modules/level-read-stream/index.js:80:5)
      at Object.getStream (lib/levelgraph.js:60:20)
      at JoinStream.transform [as _transform] (lib/joinstream.js:95:30)
      at Transform._write (node_modules/readable-stream/lib/internal/streams/transform.js:153:8)
      at writeOrBuffer (node_modules/readable-stream/lib/internal/streams/writable.js:334:12)
      at _write (node_modules/readable-stream/lib/internal/streams/writable.js:283:10)
      at Writable.end (node_modules/readable-stream/lib/internal/streams/writable.js:539:17)
      at /Users/finwo/src/finwo/levelgraph/lib/levelgraph.js:150:18
      at /Users/finwo/src/finwo/levelgraph/lib/queryplanner.js:93:7
      at NoResultsHolder.release (node_modules/fastparallel/parallel.js:139:9)
      at process.processTicksAndRejections (node:internal/process/task_queues:77:11)

With method being values, this leads me to believe the older levelup interface is not supported by the level-read-stream package.

I'll certainly have to fix this some time, but for now I'd say that's out of scope for this PR, as the workaround supports both the older and newer interface.

[vweevers]

Was that when using level-mem? That needs to be replaced as well. I wouldn't recommend running old (e.g. level-mem) and new (e.g. level@8) side by side. See the table at https://github.com/Level/community?tab=readme-ov-file#how-do-i-upgrade-to-abstract-level

[finwo]

Correct, that was using level-mem. Using level@8 that could simply be replaced by new Level()?

[vweevers]

I assume that the tests here use level-mem as a lightweight in-memory db, while real users would more likely use level. Meaning you want those databases to have the same interface.

If so then replace:

const mem = require('level-mem')
const db = mem()

With:

const { MemoryLevel } = require('memory-level')
const db = new MemoryLevel()

[finwo]

Gotcha, will test locally and commit if that'll work including level-read-stream

[finwo]

@mcollina Still in doubt on the changelog that scenaristaur added, as it's current state doesn't really make sense to me.

Would the current state of this PR be fine by you code-wise?

If so, I'll start on updating the readme to match the current state, and the version bump would probably have to be a major as it's breaking changes for people on older versions of leveldb.

[mcollina]

Amazing Work!

[mcollina]

Can you update CI to support only Node v18 an v20? I'll bump a major anyway.

[finwo]

Sure, I'll make it run 18/20

[finwo]

One more issue I have with the contributor table: it seems jez0990 has removed their github profile. Should we hunt for their current online presence or just leave it as-is?

[mcollina]

lgtm