Replace xtend with Object.assign()

lib/levelup.js

@@ -2,7 +2,6 @@
 
 const EventEmitter = require('events').EventEmitter
 const inherits = require('util').inherits
-const extend = require('xtend')
 const DeferredLevelDOWN = require('deferred-leveldown')
 const IteratorStream = require('level-iterator-stream')
 const Batch = require('./batch')
@@ -277,19 +276,19 @@ LevelUP.prototype.clear = function (options, callback) {
 
 LevelUP.prototype.readStream =
 LevelUP.prototype.createReadStream = function (options) {
-  options = extend({ keys: true, values: true }, options)
+  options = Object.assign({ keys: true, values: true }, options)
   if (typeof options.limit !== 'number') { options.limit = -1 }
   return new IteratorStream(this.db.iterator(options), options)
 }
 
 LevelUP.prototype.keyStream =
 LevelUP.prototype.createKeyStream = function (options) {
-  return this.createReadStream(extend(options, { keys: true, values: false }))
+  return this.createReadStream(Object.assign({}, options, { keys: true, values: false }))
 }
 
 LevelUP.prototype.valueStream =
 LevelUP.prototype.createValueStream = function (options) {
-  return this.createReadStream(extend(options, { keys: false, values: true }))
+  return this.createReadStream(Object.assign({}, options, { keys: false, values: true }))
 }
 
 LevelUP.prototype.toString = function () {

package.json

@@ -18,8 +18,7 @@
     "deferred-leveldown": "~5.3.0",
     "level-errors": "^3.0.0",
     "level-iterator-stream": "^5.0.0",
-    "level-supports": "^2.0.0",
-    "xtend": "~4.0.0"
+    "level-supports": "^2.0.0"
   },
   "devDependencies": {
     "after": "^0.8.2",

test/util/rs-factory.js

@@ -1,11 +1,9 @@
 'use strict'
 
-const xtend = require('xtend')
-
 module.exports = function (testCommon) {
   return function createReadStream (db, options) {
     if (!testCommon.encodings) {
-      options = xtend(options, {
+      options = Object.assign({}, options, {
         keyAsBuffer: false,
         valueAsBuffer: false
       })