feat(array): impl faster splice one element on array

.travis.yml

@@ -12,3 +12,4 @@ script:
 after_script:
   - 'npm i codecov && codecov'
   - 'node benchmark/map.js'
+  - 'node benchmark/array_splice.js'

benchmark/array_splice.js

@@ -0,0 +1,148 @@
+/**
+ * Copyright(c) node-modules and other contributors.
+ * MIT Licensed
+ *
+ * Authors:
+ *   fengmk2 <fengmk2@gmail.com> (http://fengmk2.com)
+ */
+
+'use strict';
+
+/**
+ * Module dependencies.
+ */
+
+var crypto = require('crypto');
+var utility = require('../');
+
+var Benchmark = require('benchmark');
+var benchmarks = require('beautify-benchmark');
+var suite = new Benchmark.Suite();
+
+function arraySplice(array, index) {
+  array.splice(index, 1);
+  return array;
+}
+
+function spliceOne(array, index) {
+  for (var i = index, k = i + 1, n = array.length; k < n; i += 1, k += 1) {
+    array[i] = array[k];
+  }
+  array.pop();
+  return array;
+}
+
+class SubArray extends Array {
+  spliceOne(index) {
+    for (let i = index, k = i + 1, n = this.length; k < n; i += 1, k += 1) {
+      this[i] = this[k];
+    }
+    this.pop();
+    return this;
+  }
+}
+
+console.log('arraySplice([1, 2, 3], 1): %j', arraySplice([1, 2, 3], 1));
+console.log('new SubArray(1, 2, 3).spliceOne(1): %j', new SubArray(1, 2, 3).spliceOne(1));
+console.log('spliceOne([1, 2, 3], 1): %j', spliceOne([1, 2, 3], 1));
+console.log('arraySplice([1, 2, 3, 4, 5, 6, 7, 8, 9], 6): %j',
+  arraySplice([1, 2, 3, 4, 5, 6, 7, 8, 9], 6));
+console.log('new SubArray(1, 2, 3, 4, 5, 6, 7, 8, 9).spliceOne(6): %j',
+  new SubArray(1, 2, 3, 4, 5, 6, 7, 8, 9).spliceOne(6));
+console.log('spliceOne([1, 2, 3, 4, 5, 6, 7, 8, 9], 6): %j',
+  spliceOne([1, 2, 3, 4, 5, 6, 7, 8, 9], 6));
+
+suite
+
+.add('arraySplice([1, 2, 3], 1)', function() {
+  arraySplice([1, 2, 3], 1);
+})
+.add('new SubArray(1, 2, 3).spliceOne(1)', function() {
+  new SubArray(1, 2, 3).spliceOne(1);
+})
+.add('spliceOne([1, 2, 3], 1)', function() {
+  spliceOne([1, 2, 3], 1);
+})
+
+.add('arraySplice([1, 2, 3, 4, 5, 6, 7, 8, 9], 6)', function() {
+  arraySplice([1, 2, 3, 4, 5, 6, 7, 8, 9], 6);
+})
+.add('new SubArray(1, 2, 3, 4, 5, 6, 7, 8, 9).spliceOne(6)', function() {
+  new SubArray(1, 2, 3, 4, 5, 6, 7, 8, 9).spliceOne(6);
+})
+.add('spliceOne([1, 2, 3, 4, 5, 6, 7, 8, 9], 6)', function() {
+  spliceOne([1, 2, 3, 4, 5, 6, 7, 8, 9], 6);
+})
+
+.add('arraySplice(new Array(20), 11)', function() {
+  arraySplice(new Array(20), 11);
+})
+.add('new SubArray(new Array(20)).spliceOne(11)', function() {
+  new SubArray(new Array(20)).spliceOne(11);
+})
+.add('spliceOne(new Array(20), 11)', function() {
+  spliceOne(new Array(20), 11);
+})
+
+.add('arraySplice(new Array(50), 30)', function() {
+  arraySplice(new Array(50), 30);
+})
+.add('new SubArray(new Array(50)).spliceOne(30)', function() {
+  new SubArray(new Array(50)).spliceOne(30);
+})
+.add('spliceOne(new Array(50), 30)', function() {
+  spliceOne(new Array(50), 30);
+})
+
+.add('arraySplice(new Array(100), 80)', function() {
+  arraySplice(new Array(100), 80);
+})
+.add('new SubArray(new Array(100)).spliceOne(80)', function() {
+  new SubArray(new Array(100)).spliceOne(80);
+})
+.add('spliceOne(new Array(100), 80)', function() {
+  spliceOne(new Array(100), 80);
+})
+
+
+.on('cycle', function(event) {
+  benchmarks.add(event.target);
+})
+.on('start', function(event) {
+  console.log('\n  map Benchmark\n  node version: %s, date: %s\n  Starting...',
+    process.version, Date());
+})
+.on('complete', function done() {
+  benchmarks.log();
+})
+.run({ 'async': false });
+
+// node benchmark/array_splice.js
+//
+// arraySplice([1, 2, 3], 1): [1,3]
+// new SubArray(1, 2, 3).spliceOne(1): [1,3]
+// spliceOne([1, 2, 3], 1): [1,3]
+// arraySplice([1, 2, 3, 4, 5, 6, 7, 8, 9], 6): [1,2,3,4,5,6,8,9]
+// new SubArray(1, 2, 3, 4, 5, 6, 7, 8, 9).spliceOne(6): [1,2,3,4,5,6,8,9]
+// spliceOne([1, 2, 3, 4, 5, 6, 7, 8, 9], 6): [1,2,3,4,5,6,8,9]
+//
+//   map Benchmark
+//   node version: v6.1.0, date: Sun May 08 2016 23:02:25 GMT+0800 (CST)
+//   Starting...
+//   15 tests completed.
+//
+//   arraySplice([1, 2, 3], 1)                            x  3,391,759 ops/sec ±1.75% (77 runs sampled)
+//   new SubArray(1, 2, 3).spliceOne(1)                   x  2,146,665 ops/sec ±2.44% (78 runs sampled)
+//   spliceOne([1, 2, 3], 1)                              x 30,957,606 ops/sec ±2.30% (76 runs sampled)
+//   arraySplice([1, 2, 3, 4, 5, 6, 7, 8, 9], 6)          x  3,393,631 ops/sec ±1.58% (81 runs sampled)
+//   new SubArray(1, 2, 3, 4, 5, 6, 7, 8, 9).spliceOne(6) x  1,898,975 ops/sec ±1.36% (81 runs sampled)
+//   spliceOne([1, 2, 3, 4, 5, 6, 7, 8, 9], 6)            x 23,286,263 ops/sec ±2.40% (72 runs sampled)
+//   arraySplice(new Array(20), 11)                       x  3,424,955 ops/sec ±1.39% (79 runs sampled)
+//   new SubArray(new Array(20)).spliceOne(11)            x  1,703,608 ops/sec ±1.43% (79 runs sampled)
+//   spliceOne(new Array(20), 11)                         x  6,371,527 ops/sec ±8.68% (71 runs sampled)
+//   arraySplice(new Array(50), 30)                       x  2,961,652 ops/sec ±3.94% (81 runs sampled)
+//   new SubArray(new Array(50)).spliceOne(30)            x  1,738,558 ops/sec ±2.28% (84 runs sampled)
+//   spliceOne(new Array(50), 30)                         x  2,887,661 ops/sec ±4.01% (74 runs sampled)
+//   arraySplice(new Array(100), 80)                      x  2,803,597 ops/sec ±2.12% (86 runs sampled)
+//   new SubArray(new Array(100)).spliceOne(80)           x  1,695,942 ops/sec ±0.91% (88 runs sampled)
+//   spliceOne(new Array(100), 80)                        x  3,175,629 ops/sec ±1.28% (86 runs sampled)

lib/array.js

@@ -1,8 +1,9 @@
-/*!
- * utility - lib/array.js
- *
- * Copyright(c) 2012 - 2014 fengmk2 <fengmk2@gmail.com>
+/**
+ * Copyright(c) node-modules and other contributors.
  * MIT Licensed
+ *
+ * Authors:
+ *   fengmk2 <fengmk2@gmail.com> (http://fengmk2.com)
  */
 
 "use strict";
@@ -27,3 +28,30 @@ exports.randomSlice = function randomSlice(arr, num) {
   }
   return a;
 };
+
+/**
+ * Remove one exists element from an array
+ * @param {Array} arr
+ * @param  {Number} index - remove element index
+ * @return {Array} the array instance
+ */
+exports.spliceOne = function spliceOne(arr, index) {
+  if (index < 0) {
+    index = arr.length + index;
+    // still negative, not found element
+    if (index < 0) {
+      return arr;
+    }
+  }
+
+  // don't touch
+  if (index >= arr.length) {
+    return arr;
+  }
+
+  for (var i = index, k = i + 1, n = arr.length; k < n; i += 1, k += 1) {
+    arr[i] = arr[k];
+  }
+  arr.pop();
+  return arr;
+};

package.json

@@ -7,7 +7,7 @@
     "lib"
   ],
   "scripts": {
-    "test": "ava test/**/*.test.js",
+    "test": "npm run lint && ava test/**/*.test.js",
     "test-cov": "nyc ava test/**/*.test.js && nyc report --reporter=lcov",
     "lint": "jshint .",
     "ci": "npm run lint && npm run test-cov",

test/array.test.js

@@ -26,3 +26,24 @@ test('randomSlice() should return sub items', t => {
   t.deepEqual(utils.randomSlice(arr, 0), arr);
   t.is(utils.randomSlice(arr, 6).length, 6);
 });
+
+test('spliceOne() should work', t => {
+  t.deepEqual(utils.spliceOne([1, 2, 3], 0), [2, 3]);
+  t.deepEqual(utils.spliceOne([1, 2, 3], 1), [1, 3]);
+  t.deepEqual(utils.spliceOne([1, 2, 3], 2), [1, 2]);
+  t.deepEqual(utils.spliceOne([1, 2, 3], 3), [1, 2, 3]);
+  t.deepEqual(utils.spliceOne([1, 2, 3], 4), [1, 2, 3]);
+  t.deepEqual(utils.spliceOne([1, 2, 3], 5), [1, 2, 3]);
+  t.deepEqual(utils.spliceOne([1, 2, 3], -0), [2, 3]);
+  t.deepEqual(utils.spliceOne([1, 2, 3], -1), [1, 2]);
+  t.deepEqual(utils.spliceOne([1, 2, 3], -2), [1, 3]);
+  t.deepEqual(utils.spliceOne([1, 2, 3], -3), [2, 3]);
+  t.deepEqual(utils.spliceOne([1, 2, 3], -4), [1, 2, 3]);
+  t.deepEqual(utils.spliceOne([1, 2, 3], -5), [1, 2, 3]);
+  t.deepEqual(utils.spliceOne([1, 2, 3], 100), [1, 2, 3]);
+
+  t.deepEqual(utils.spliceOne([1], 0), []);
+  t.deepEqual(utils.spliceOne([1], 1), [1]);
+  t.deepEqual(utils.spliceOne([], 0), []);
+  t.deepEqual(utils.spliceOne([], 100), []);
+});