Modernize syntax and bump standard (Level/community#98)

Author: vweevers

.github/dependabot.yml

@@ -5,7 +5,5 @@ updates:
     schedule:
       interval: monthly
     ignore:
-      - dependency-name: buffer
       - dependency-name: dependency-check
       - dependency-name: uuid
-      - dependency-name: standard

index.js

@@ -4,16 +4,16 @@
 
 module.exports = Level
 
-var AbstractLevelDOWN = require('abstract-leveldown').AbstractLevelDOWN
-var inherits = require('inherits')
-var Iterator = require('./iterator')
-var serialize = require('./util/serialize')
-var deserialize = require('./util/deserialize')
-var support = require('./util/support')
-var clear = require('./util/clear')
-var createKeyRange = require('./util/key-range')
+const AbstractLevelDOWN = require('abstract-leveldown').AbstractLevelDOWN
+const inherits = require('inherits')
+const Iterator = require('./iterator')
+const serialize = require('./util/serialize')
+const deserialize = require('./util/deserialize')
+const support = require('./util/support')
+const clear = require('./util/clear')
+const createKeyRange = require('./util/key-range')
 
-var DEFAULT_PREFIX = 'level-js-'
+const DEFAULT_PREFIX = 'level-js-'
 
 function Level (location, opts) {
   if (!(this instanceof Level)) return new Level(location, opts)
@@ -41,34 +41,33 @@ inherits(Level, AbstractLevelDOWN)
 Level.prototype.type = 'level-js'
 
 Level.prototype._open = function (options, callback) {
-  var req = indexedDB.open(this.prefix + this.location, this.version)
-  var self = this
+  const req = indexedDB.open(this.prefix + this.location, this.version)
 
   req.onerror = function () {
     callback(req.error || new Error('unknown error'))
   }
 
-  req.onsuccess = function () {
-    self.db = req.result
+  req.onsuccess = () => {
+    this.db = req.result
     callback()
   }
 
-  req.onupgradeneeded = function (ev) {
-    var db = ev.target.result
+  req.onupgradeneeded = (ev) => {
+    const db = ev.target.result
 
-    if (!db.objectStoreNames.contains(self.location)) {
-      db.createObjectStore(self.location)
+    if (!db.objectStoreNames.contains(this.location)) {
+      db.createObjectStore(this.location)
     }
   }
 }
 
 Level.prototype.store = function (mode) {
-  var transaction = this.db.transaction([this.location], mode)
+  const transaction = this.db.transaction([this.location], mode)
   return transaction.objectStore(this.location)
 }
 
 Level.prototype.await = function (request, callback) {
-  var transaction = request.transaction
+  const transaction = request.transaction
 
   // Take advantage of the fact that a non-canceled request error aborts
   // the transaction. I.e. no need to listen for "request.onerror".
@@ -82,10 +81,11 @@ Level.prototype.await = function (request, callback) {
 }
 
 Level.prototype._get = function (key, options, callback) {
-  var store = this.store('readonly')
+  const store = this.store('readonly')
+  let req
 
   try {
-    var req = store.get(key)
+    req = store.get(key)
   } catch (err) {
     return this._nextTick(callback, err)
   }
@@ -103,10 +103,11 @@ Level.prototype._get = function (key, options, callback) {
 }
 
 Level.prototype._del = function (key, options, callback) {
-  var store = this.store('readwrite')
+  const store = this.store('readwrite')
+  let req
 
   try {
-    var req = store.delete(key)
+    req = store.delete(key)
   } catch (err) {
     return this._nextTick(callback, err)
   }
@@ -115,12 +116,13 @@ Level.prototype._del = function (key, options, callback) {
 }
 
 Level.prototype._put = function (key, value, options, callback) {
-  var store = this.store('readwrite')
+  const store = this.store('readwrite')
+  let req
 
   try {
     // Will throw a DataError or DataCloneError if the environment
     // does not support serializing the key or value respectively.
-    var req = store.put(value, key)
+    req = store.put(value, key)
   } catch (err) {
     return this._nextTick(callback, err)
   }
@@ -143,10 +145,10 @@ Level.prototype._iterator = function (options) {
 Level.prototype._batch = function (operations, options, callback) {
   if (operations.length === 0) return this._nextTick(callback)
 
-  var store = this.store('readwrite')
-  var transaction = store.transaction
-  var index = 0
-  var error
+  const store = this.store('readwrite')
+  const transaction = store.transaction
+  let index = 0
+  let error
 
   transaction.onabort = function () {
     callback(error || transaction.error || new Error('aborted by user'))
@@ -158,11 +160,13 @@ Level.prototype._batch = function (operations, options, callback) {
 
   // Wait for a request to complete before making the next, saving CPU.
   function loop () {
-    var op = operations[index++]
-    var key = op.key
+    const op = operations[index++]
+    const key = op.key
+
+    let req
 
     try {
-      var req = op.type === 'del' ? store.delete(key) : store.put(op.value, key)
+      req = op.type === 'del' ? store.delete(key) : store.put(op.value, key)
     } catch (err) {
       error = err
       transaction.abort()
@@ -178,8 +182,11 @@ Level.prototype._batch = function (operations, options, callback) {
 }
 
 Level.prototype._clear = function (options, callback) {
+  let keyRange
+  let req
+
   try {
-    var keyRange = createKeyRange(options)
+    keyRange = createKeyRange(options)
   } catch (e) {
     // The lower key is greater than the upper key.
     // IndexedDB throws an error, but we'll just do nothing.
@@ -193,8 +200,8 @@ Level.prototype._clear = function (options, callback) {
   }
 
   try {
-    var store = this.store('readwrite')
-    var req = keyRange ? store.delete(keyRange) : store.clear()
+    const store = this.store('readwrite')
+    req = keyRange ? store.delete(keyRange) : store.clear()
   } catch (err) {
     return this._nextTick(callback, err)
   }
@@ -213,9 +220,9 @@ Level.prototype.upgrade = function (callback) {
     return this._nextTick(callback, new Error('cannot upgrade() before open()'))
   }
 
-  var it = this.iterator()
-  var batchOptions = {}
-  var self = this
+  const it = this.iterator()
+  const batchOptions = {}
+  const self = this
 
   it._deserializeKey = it._deserializeValue = identity
   next()
@@ -230,8 +237,8 @@ Level.prototype.upgrade = function (callback) {
       return finish(err)
     }
 
-    var newKey = self._serializeKey(deserialize(key, true))
-    var newValue = self._serializeValue(deserialize(value, true))
+    const newKey = self._serializeKey(deserialize(key, true))
+    const newValue = self._serializeValue(deserialize(value, true))
 
     // To bypass serialization on the old key, use _batch() instead of batch().
     // NOTE: if we disable snapshotting (#86) this could lead to a loop of
@@ -259,7 +266,7 @@ Level.destroy = function (location, prefix, callback) {
     callback = prefix
     prefix = DEFAULT_PREFIX
   }
-  var request = indexedDB.deleteDatabase(prefix + location)
+  const request = indexedDB.deleteDatabase(prefix + location)
   request.onsuccess = function () {
     callback()
   }

iterator.js

@@ -1,10 +1,10 @@
 'use strict'
 
-var inherits = require('inherits')
-var AbstractIterator = require('abstract-leveldown').AbstractIterator
-var createKeyRange = require('./util/key-range')
-var deserialize = require('./util/deserialize')
-var noop = function () {}
+const inherits = require('inherits')
+const AbstractIterator = require('abstract-leveldown').AbstractIterator
+const createKeyRange = require('./util/key-range')
+const deserialize = require('./util/deserialize')
+const noop = function () {}
 
 module.exports = Iterator
 
@@ -30,8 +30,10 @@ function Iterator (db, location, options) {
     return
   }
 
+  let keyRange
+
   try {
-    var keyRange = createKeyRange(options)
+    keyRange = createKeyRange(options)
   } catch (e) {
     // The lower key is greater than the upper key.
     // IndexedDB throws an error, but we'll just return 0 results.
@@ -45,25 +47,24 @@ function Iterator (db, location, options) {
 inherits(Iterator, AbstractIterator)
 
 Iterator.prototype.createIterator = function (location, keyRange, reverse) {
-  var self = this
-  var transaction = this.db.db.transaction([location], 'readonly')
-  var store = transaction.objectStore(location)
-  var req = store.openCursor(keyRange, reverse ? 'prev' : 'next')
-
-  req.onsuccess = function (ev) {
-    var cursor = ev.target.result
-    if (cursor) self.onItem(cursor)
+  const transaction = this.db.db.transaction([location], 'readonly')
+  const store = transaction.objectStore(location)
+  const req = store.openCursor(keyRange, reverse ? 'prev' : 'next')
+
+  req.onsuccess = (ev) => {
+    const cursor = ev.target.result
+    if (cursor) this.onItem(cursor)
   }
 
   this._transaction = transaction
 
   // If an error occurs (on the request), the transaction will abort.
-  transaction.onabort = function () {
-    self.onAbort(self._transaction.error || new Error('aborted by user'))
+  transaction.onabort = () => {
+    this.onAbort(this._transaction.error || new Error('aborted by user'))
   }
 
-  transaction.oncomplete = function () {
-    self.onComplete()
+  transaction.oncomplete = () => {
+    this.onComplete()
   }
 }
 
@@ -98,12 +99,12 @@ Iterator.prototype.maybeNext = function () {
 Iterator.prototype._next = function (callback) {
   if (this._aborted) {
     // The error should be picked up by either next() or end().
-    var err = this._error
+    const err = this._error
     this._error = null
     this._nextTick(callback, err)
   } else if (this._cache.length > 0) {
-    var key = this._cache.shift()
-    var value = this._cache.shift()
+    let key = this._cache.shift()
+    let value = this._cache.shift()
 
     if (this._keys && key !== undefined) {
       key = this._deserializeKey(key, this._keyAsBuffer)

package.json

@@ -38,7 +38,7 @@
     "level-community": "^3.0.0",
     "level-concat-iterator": "^2.0.0",
     "nyc": "^15.0.0",
-    "standard": "^15.0.1",
+    "standard": "^16.0.3",
     "tape": "^5.0.0",
     "uuid": "^3.3.2"
   },