From a6f80810b2200da0cbb389f3945513a0b99c9499 Mon Sep 17 00:00:00 2001
From: tuhm1 <50200070+tuhm1@users.noreply.github.com>
Date: Fri, 27 Dec 2024 16:38:57 +0700
Subject: [PATCH] perf(pull): faster `pull` (#915)

* improve pull

* fix lint error

* refactor to use hasOwn

---------

Co-authored-by: Sojin Park <raon0211@gmail.com>
---
 benchmarks/performance/pull.bench.ts | 42 ++++++++++++++++++++++++++++
 src/array/pull.ts                    | 15 ++++++++--
 2 files changed, 55 insertions(+), 2 deletions(-)
 create mode 100644 benchmarks/performance/pull.bench.ts

diff --git a/benchmarks/performance/pull.bench.ts b/benchmarks/performance/pull.bench.ts
new file mode 100644
index 000000000..c889a08bb
--- /dev/null
+++ b/benchmarks/performance/pull.bench.ts
@@ -0,0 +1,42 @@
+import { bench, describe } from 'vitest';
+import { pull as pullToolkit } from 'es-toolkit/compat';
+import { pull as pullLodash } from 'lodash';
+
+describe('pull array size 100', () => {
+  const array = [...Array(100)].map((_, i) => i);
+  const even = [...Array(50)].map((_, i) => i * 2);
+
+  bench('es-toolkit/pull', () => {
+    pullToolkit([...array], even);
+  });
+
+  bench('lodash/pull', () => {
+    pullLodash([...array], ...even);
+  });
+});
+
+describe('pull array size 1000', () => {
+  const array = [...Array(1000)].map((_, i) => i);
+  const even = [...Array(500)].map((_, i) => i * 2);
+
+  bench('es-toolkit/pull', () => {
+    pullToolkit([...array], [...even]);
+  });
+
+  bench('lodash/pull', () => {
+    pullLodash([...array], ...even);
+  });
+});
+
+describe('pull array size 10000', () => {
+  const array = [...Array(10000)].map((_, i) => i);
+  const even = [...Array(5000)].map((_, i) => i * 2);
+
+  bench('es-toolkit/pull', () => {
+    pullToolkit([...array], [...even]);
+  });
+
+  bench('lodash/pull', () => {
+    pullLodash([...array], ...even);
+  });
+});
diff --git a/src/array/pull.ts b/src/array/pull.ts
index 51d15019d..c12b10a80 100644
--- a/src/array/pull.ts
+++ b/src/array/pull.ts
@@ -16,12 +16,23 @@
  */
 export function pull<T>(arr: T[], valuesToRemove: readonly unknown[]): T[] {
   const valuesSet = new Set(valuesToRemove);
+  let resultIndex = 0;
 
-  for (let i = arr.length - 1; i >= 0; i--) {
+  for (let i = 0; i < arr.length; i++) {
     if (valuesSet.has(arr[i])) {
-      arr.splice(i, 1);
+      continue;
     }
+
+    // For handling sparse arrays
+    if (!Object.hasOwn(arr, i)) {
+      delete arr[resultIndex++];
+      continue;
+    }
+
+    arr[resultIndex++] = arr[i];
   }
 
+  arr.length = resultIndex;
+
   return arr;
 }