Initial

resources/app/node_modules/abstract-level/lib/default-kv-iterator.js

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+'use strict'
+
+const { AbstractKeyIterator, AbstractValueIterator } = require('../abstract-iterator')
+
+const kIterator = Symbol('iterator')
+const kCallback = Symbol('callback')
+const kHandleOne = Symbol('handleOne')
+const kHandleMany = Symbol('handleMany')
+
+class DefaultKeyIterator extends AbstractKeyIterator {
+  constructor (db, options) {
+    super(db, options)
+
+    this[kIterator] = db.iterator({ ...options, keys: true, values: false })
+    this[kHandleOne] = this[kHandleOne].bind(this)
+    this[kHandleMany] = this[kHandleMany].bind(this)
+  }
+}
+
+class DefaultValueIterator extends AbstractValueIterator {
+  constructor (db, options) {
+    super(db, options)
+
+    this[kIterator] = db.iterator({ ...options, keys: false, values: true })
+    this[kHandleOne] = this[kHandleOne].bind(this)
+    this[kHandleMany] = this[kHandleMany].bind(this)
+  }
+}
+
+for (const Iterator of [DefaultKeyIterator, DefaultValueIterator]) {
+  const keys = Iterator === DefaultKeyIterator
+  const mapEntry = keys ? (entry) => entry[0] : (entry) => entry[1]
+
+  Iterator.prototype._next = function (callback) {
+    this[kCallback] = callback
+    this[kIterator].next(this[kHandleOne])
+  }
+
+  Iterator.prototype[kHandleOne] = function (err, key, value) {
+    const callback = this[kCallback]
+    if (err) callback(err)
+    else callback(null, keys ? key : value)
+  }
+
+  Iterator.prototype._nextv = function (size, options, callback) {
+    this[kCallback] = callback
+    this[kIterator].nextv(size, options, this[kHandleMany])
+  }
+
+  Iterator.prototype._all = function (options, callback) {
+    this[kCallback] = callback
+    this[kIterator].all(options, this[kHandleMany])
+  }
+
+  Iterator.prototype[kHandleMany] = function (err, entries) {
+    const callback = this[kCallback]
+    if (err) callback(err)
+    else callback(null, entries.map(mapEntry))
+  }
+
+  Iterator.prototype._seek = function (target, options) {
+    this[kIterator].seek(target, options)
+  }
+
+  Iterator.prototype._close = function (callback) {
+    this[kIterator].close(callback)
+  }
+}
+
+// Internal utilities, should be typed as AbstractKeyIterator and AbstractValueIterator
+exports.DefaultKeyIterator = DefaultKeyIterator
+exports.DefaultValueIterator = DefaultValueIterator