Implement db#clear across the board

[vweevers]

Background: https://github.com/Level/abstract-leveldown/pull/24#issuecomment-397760287.

Phase 1: get it working

• [x] The default implementation of clear() deletes entries with an iterator. It can take range options, e.g. clear({ gt: 'foo' }) and should serialize them
  • [x] PR: https://github.com/Level/abstract-leveldown/pull/310
  • [x] Release: 6.1.0
• [x] encoding-down can call this.db.clear() and should encode the range options
  • [x] PR: https://github.com/Level/encoding-down/pull/89)
  • [x] Release: 6.2.0
• [x] leveldown
  • [x] PR: https://github.com/Level/leveldown/pull/660
  • [x] Release: 5.2.0
• [x] deferred-leveldown should defer it
  • [x] PR: https://github.com/Level/deferred-leveldown/pull/72
  • [x] Release: 5.2.0
• [x] levelup
  • [x] PR: https://github.com/Level/levelup/pull/669
  • [x] Release: 4.2.0
• [x] memdown
  • [x] PR: https://github.com/Level/memdown/pull/194
  • [x] Release: 5.0.0
• [x] level-packager (bump dependencies to prevent dedupe)
  • [x] Commit: Level/packager@a293d30
  • [x] Release: 5.0.3
• [x] level-js
  • [x] PR: https://github.com/Level/level-js/pull/182
  • [x] Release: 5.0.0
• [x] level
  • [x] PR or commit: https://github.com/Level/level/pull/162, https://github.com/Level/level/commit/5efdc82e9064e8f1826c708dccd28c85306b759a
  • [x] Release: 6.0.0
• [x] level-mem (bump dependencies to prevent dedupe)
  • [x] Commit: Level/mem@baec173
  • [x] Release: 5.0.1
• [x] rocksdb
  • [x] Commit: https://github.com/Level/rocksdb/commit/b9d58fbc9266aa3d1143dd5bc65a0cdea225feab
  • [x] Release: 4.1.0
• [x] level-rocksdb (bump dependencies to prevent dedupe)
• [x] subleveldown uses the range options to implement clear on a sublevel
  • [x] PR: https://github.com/Level/subleveldown/pull/74
  • [x] Release: 4.1.2
• [x] multileveldown (and by extension, level-party)
  • [x] https://github.com/Level/multileveldown/commit/47e0137fc5244d291d696296ef23da32ff7d8a39
  • [x] Release: 5.0.0
• [x] leveldown-hyper and level-hyper (slated to be deprecated)

Phase 2: optimize

• [x] memdown: https://github.com/Level/memdown/pull/213
• [x] leveldown can implement it natively (https://github.com/Level/leveldown/issues/680)
• [x] rocksdb: https://github.com/Level/rocksdb/pull/184 (5.2.0)
• [x] level-js can call either IDBObjectStore#clear() or IDBObjectStore#delete(range)

On the side

• [x] Use it in mafintosh/level-temp (old)
• [x] Add notice to Raynos/level-delete-range (old)
• [x] https://github.com/juliangruber/level-delete-stream/pull/3
• [x] Send PR to noffle/kappa-view-level for its clearIndex()

[ralphtheninja]

Very nice. I especially like the subleveldown feature, like emptying a bucket of stuff.

[vweevers]

Relevant leveldown issue: https://github.com/Level/leveldown/issues/9.

[vweevers]

Ah, the level-concat-iterator dependency comes in handy for the default implementation of _clear :)

[ralphtheninja]

Ah, the level-concat-iterator dependency comes in handy for the default implementation of _clear :)

Good. Then we don't have to feel so bad about including it :wink:

[vweevers]

Ah, the level-concat-iterator dependency comes in handy for the default implementation of _clear :)

Scratch that. Would choke on many keys.

[vweevers]

Because abstract-leveldown@6.1.0 now has a clear() method, I'm moving this issue to community to track overall progress.