fix(isBuffer): add browser export condition to avoid 44KB Buffer polyfill (#1671)

* fix[isBuffer]: add browser export condition to avoid 28KB Buffer polyfill

* fix: read UMD output path from package.json instead of hardcoding

* use globalThis.Buffer instead

* rollup

* comment

---------

Co-authored-by: Sojin Park <raon0211@gmail.com>

Author: jantimon

src/_internal/globalThis.ts

@@ -0,0 +1,12 @@
+// eslint-disable-next-line @typescript-eslint/naming-convention
+const globalThis_ =
+  (typeof globalThis === 'object' && globalThis) ||
+  (typeof window === 'object' && window) ||
+  (typeof self === 'object' && self) ||
+  (typeof global === 'object' && global) ||
+  (function () {
+    return this;
+  })() ||
+  Function('return this')();
+
+export { globalThis_ as globalThis };

src/compat/object/mergeWith.ts

@@ -1,6 +1,7 @@
 import { cloneDeep } from './cloneDeep.ts';
 import { isUnsafeProperty } from '../../_internal/isUnsafeProperty.ts';
 import { clone } from '../../object/clone.ts';
+import { isBuffer } from '../../predicate/isBuffer.ts';
 import { isPrimitive } from '../../predicate/isPrimitive.ts';
 import { getSymbols } from '../_internal/getSymbols.ts';
 import { isArguments } from '../predicate/isArguments.ts';
@@ -9,12 +10,6 @@ import { isObjectLike } from '../predicate/isObjectLike.ts';
 import { isPlainObject } from '../predicate/isPlainObject.ts';
 import { isTypedArray } from '../predicate/isTypedArray.ts';
 
-declare let Buffer:
-  | {
-      isBuffer: (a: any) => boolean;
-    }
-  | undefined;
-
 type MergeWithCustomizer = (objValue: any, srcValue: any, key: string, object: any, source: any, stack: any) => any;
 
 /**
@@ -288,7 +283,7 @@ function mergeWithDeep(
       targetValue = { ...targetValue };
     }
 
-    if (typeof Buffer !== 'undefined' && Buffer.isBuffer(sourceValue)) {
+    if (isBuffer(sourceValue)) {
       sourceValue = cloneDeep(sourceValue);
     }
 

src/compat/predicate/isEmpty.ts

@@ -1,15 +1,10 @@
 import { isArguments } from './isArguments.ts';
 import { isArrayLike } from './isArrayLike.ts';
 import { isTypedArray } from './isTypedArray.ts';
+import { isBuffer } from '../../predicate/isBuffer.ts';
 import type { EmptyObjectOf } from '../_internal/EmptyObjectOf.ts';
 import { isPrototype } from '../_internal/isPrototype.ts';
 
-declare let Buffer:
-  | {
-      isBuffer: (a: any) => boolean;
-    }
-  | undefined;
-
 export function isEmpty<T extends { __trapAny: any }>(value?: T): boolean;
 export function isEmpty(value: string): value is '';
 export function isEmpty(value: Map<any, any> | Set<any> | ArrayLike<any> | null | undefined): boolean;
@@ -53,7 +48,7 @@ export function isEmpty(value?: unknown): boolean {
     if (
       typeof (value as any).splice !== 'function' &&
       typeof value !== 'string' &&
-      (typeof Buffer === 'undefined' || !Buffer.isBuffer(value)) &&
+      !isBuffer(value) &&
       !isTypedArray(value) &&
       !isArguments(value)
     ) {

src/object/cloneDeepWith.ts

@@ -24,6 +24,7 @@ import {
   uint16ArrayTag,
   uint32ArrayTag,
 } from '../compat/_internal/tags.ts';
+import { isBuffer } from '../predicate/isBuffer.ts';
 import { isPrimitive } from '../predicate/isPrimitive.ts';
 import { isTypedArray } from '../predicate/isTypedArray.ts';
 
@@ -152,12 +153,8 @@ export function cloneDeepWithImpl<T>(
     return result as T;
   }
 
-  // eslint-disable-next-line @typescript-eslint/ban-ts-comment
-  // @ts-ignore
-  if (typeof Buffer !== 'undefined' && Buffer.isBuffer(valueToClone)) {
-    // eslint-disable-next-line @typescript-eslint/ban-ts-comment
-    // @ts-ignore
-    return valueToClone.subarray() as T;
+  if (isBuffer(valueToClone)) {
+    return (valueToClone as any).subarray() as T;
   }
 
   if (isTypedArray(valueToClone)) {

src/predicate/isBuffer.ts

@@ -1,8 +1,4 @@
-declare let Buffer:
-  | {
-      isBuffer: (a: any) => boolean;
-    }
-  | undefined;
+import { globalThis } from '../_internal/globalThis';
 
 /**
  * Checks if the given value is a Buffer instance.
@@ -25,5 +21,5 @@ declare let Buffer:
 export function isBuffer(x: unknown): boolean {
   // eslint-disable-next-line
   // @ts-ignore
-  return typeof Buffer !== 'undefined' && Buffer.isBuffer(x);
+  return typeof globalThis.Buffer !== 'undefined' && globalThis.Buffer.isBuffer(x);
 }

src/predicate/isEqualWith.ts

@@ -1,3 +1,4 @@
+import { isBuffer } from './isBuffer.ts';
 import { isPlainObject } from './isPlainObject.ts';
 import { getSymbols } from '../compat/_internal/getSymbols.ts';
 import { getTag } from '../compat/_internal/getTag.ts';
@@ -31,12 +32,6 @@ import {
 } from '../compat/_internal/tags.ts';
 import { eq } from '../compat/util/eq.ts';
 
-declare let Buffer:
-  | {
-      isBuffer: (a: any) => boolean;
-    }
-  | undefined;
-
 /**
  * Compares two values for equality using a custom comparison function.
  *
@@ -255,7 +250,7 @@ function areObjectsEqual(
       case float32ArrayTag:
       case float64ArrayTag: {
         // Buffers are also treated as [object Uint8Array]s.
-        if (typeof Buffer !== 'undefined' && Buffer.isBuffer(a) !== Buffer.isBuffer(b)) {
+        if (isBuffer(a) !== isBuffer(b)) {
           return false;
         }