diff --git a/src/compat/array/flattenDeep.ts b/src/compat/array/flattenDeep.ts
index ccdb7380..3d51ebb9 100644
--- a/src/compat/array/flattenDeep.ts
+++ b/src/compat/array/flattenDeep.ts
@@ -1,4 +1,4 @@
-import { flatten } from './flatten';
+import { flatten } from './flatten.ts';
 
 /**
  * Utility type for recursively unpacking nested array types to extract the type of the innermost element
diff --git a/src/compat/array/flattenDepth.ts b/src/compat/array/flattenDepth.ts
index 3f3979fc..09d59b9f 100644
--- a/src/compat/array/flattenDepth.ts
+++ b/src/compat/array/flattenDepth.ts
@@ -1,4 +1,4 @@
-import { flatten } from './flatten';
+import { flatten } from './flatten.ts';
 
 /**
  * Flattens an array up to the specified depth.
diff --git a/src/function/unary.ts b/src/function/unary.ts
index da44f595..31c84a0d 100644
--- a/src/function/unary.ts
+++ b/src/function/unary.ts
@@ -1,4 +1,4 @@
-import { ary } from './ary';
+import { ary } from './ary.ts';
 
 /**
  * Creates a function that accepts up to one argument, ignoring any additional arguments.
diff --git a/src/predicate/isEqual.ts b/src/predicate/isEqual.ts
index c30f21b8..e94350f3 100644
--- a/src/predicate/isEqual.ts
+++ b/src/predicate/isEqual.ts
@@ -4,6 +4,10 @@ import { getSymbols } from "../compat/_internal/getSymbols.ts";
 import { getTag } from "../compat/_internal/getTag.ts";
 import { isPlainObject } from "./isPlainObject.ts";
 
+declare var Buffer: {
+  isBuffer: (a: any) => boolean;
+} | undefined;
+
 /**
  * Checks if two values are equal, including support for `Date`, `RegExp`, and deep object comparison.
  *
@@ -154,7 +158,7 @@ function areObjectsEqual(a: any, b: any, stack?: Map<any, any>) {
       case float32ArrayTag:
       case float64ArrayTag: {
         // Buffers are also treated as [object Uint8Array]s.
-        if (Buffer.isBuffer(a) !== Buffer.isBuffer(b)) {
+        if (typeof Buffer !== 'undefined' && Buffer.isBuffer(a) !== Buffer.isBuffer(b)) {
           return false;
         }