Breaking: bump readable-stream from 3 to 4

See https://github.com/nodejs/readable-stream. TLDR (because you
won't find a changelog): it fast-forwards to Node.js 18 streams and,
apart from all the changes between Node.js 10 and 18, drops support
of Internet Explorer.

README.md

@@ -42,7 +42,7 @@ ws.end()
 
 ### `ws = new WriteStream(db[, options])`
 
-Create a [writable stream](https://nodejs.org/dist/latest-v8.x/docs/api/stream.html#stream_class_stream_writable) that operates in object mode, accepting batch operations to be committed with `db.batch()` on each tick of the Node.js event loop. The optional `options` argument may contain:
+Create a [writable stream](https://nodejs.org/dist/latest-v18.x/docs/api/stream.html#stream_class_stream_writable) that operates in object mode, accepting batch operations to be committed with `db.batch()` on each tick of the Node.js event loop. The optional `options` argument may contain:
 
 - `type` (string, default: `'put'`): default batch operation type if not set on indididual operations.
 - `maxBufferLength` (number, default `Infinity`): limit the size of batches. When exceeded, the stream will stop processing writes until the current batch has been committed.

level-ws.js

@@ -8,7 +8,9 @@ class WriteStream extends Writable {
 
     super({
       objectMode: true,
-      highWaterMark: options.highWaterMark || 16
+      highWaterMark: options.highWaterMark || 16,
+      autoDestroy: true,
+      emitClose: true
     })
 
     this._options = options
@@ -17,10 +19,6 @@ class WriteStream extends Writable {
     this._flushing = false
     this._maxBufferLength = options.maxBufferLength || Infinity
     this._flush = this._flush.bind(this)
-
-    this.on('finish', () => {
-      this.emit('close')
-    })
   }
 
   _write (data, enc, next) {

package.json

@@ -14,7 +14,7 @@
     "UPGRADING.md"
   ],
   "dependencies": {
-    "readable-stream": "^3.1.0"
+    "readable-stream": "^4.0.0"
   },
   "devDependencies": {
     "hallmark": "^4.1.0",

test.js

@@ -145,7 +145,7 @@ test('race condition between two flushes', function (t, ctx, done) {
   const order = monitor(ws)
 
   ws.on('close', function () {
-    t.same(order, ['batch', 'batch', 'close'])
+    t.same(order, ['batch', 'batch', 'finish', 'close'])
 
     ctx.verify(ws, done, [
       { key: 'a', value: 'a' },