fix: Resolve TypeScript errors

Signed-off-by: Hermes Agent <hermes@nosuchhost>

client/node_modules/leveldown/iterator.js

@@ -0,0 +1,50 @@
+const util = require('util')
+const AbstractIterator = require('abstract-leveldown').AbstractIterator
+const binding = require('./binding')
+
+function Iterator (db, options) {
+  AbstractIterator.call(this, db)
+
+  this.context = binding.iterator_init(db.context, options)
+  this.cache = null
+  this.finished = false
+}
+
+util.inherits(Iterator, AbstractIterator)
+
+Iterator.prototype._seek = function (target) {
+  if (target.length === 0) {
+    throw new Error('cannot seek() to an empty target')
+  }
+
+  this.cache = null
+  binding.iterator_seek(this.context, target)
+  this.finished = false
+}
+
+Iterator.prototype._next = function (callback) {
+  var that = this
+
+  if (this.cache && this.cache.length) {
+    process.nextTick(callback, null, this.cache.pop(), this.cache.pop())
+  } else if (this.finished) {
+    process.nextTick(callback)
+  } else {
+    binding.iterator_next(this.context, function (err, array, finished) {
+      if (err) return callback(err)
+
+      that.cache = array
+      that.finished = finished
+      that._next(callback)
+    })
+  }
+
+  return this
+}
+
+Iterator.prototype._end = function (callback) {
+  delete this.cache
+  binding.iterator_end(this.context, callback)
+}
+
+module.exports = Iterator