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# is-buffer
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is-buffer provides a lightweight utility function for determining whether an object is a Buffer instance without requiring the full buffer module in browserify environments. It offers cross-platform compatibility between Node.js and browser environments while maintaining zero runtime dependencies and minimal bundle size.
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## Package Information
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- **Package Name**: is-buffer
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- **Package Type**: npm
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- **Language**: JavaScript (with TypeScript definitions)
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- **Installation**: `npm install is-buffer`
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## Core Imports
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```javascript
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const isBuffer = require('is-buffer');
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```
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For ESM:
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```javascript
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import isBuffer from 'is-buffer';
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```
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For TypeScript:
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```typescript
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import isBuffer = require('is-buffer');
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// or modern syntax:
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import isBuffer from 'is-buffer';
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```
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## Basic Usage
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```javascript
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const isBuffer = require('is-buffer');
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// Check various types
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console.log(isBuffer(Buffer.from('hello')));     // true
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console.log(isBuffer(Buffer.alloc(4)));          // true
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console.log(isBuffer('string'));                 // false
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console.log(isBuffer(null));                     // false
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console.log(isBuffer({}));                       // false
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```
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## Capabilities
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### Buffer Detection
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Determines if an object is a Buffer instance by checking the object's constructor and its isBuffer method, providing reliable detection without including the full buffer module.
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```javascript { .api }
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/**
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 * Determine if an object is a Buffer
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 * @param obj - The object to test
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 * @returns true if the object is a Buffer, false otherwise
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 */
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function isBuffer(obj: any): boolean;
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```
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**Parameters:**
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- `obj` (any): The object to test for Buffer instance
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**Returns:**
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- `boolean`: `true` if the object is a Buffer, `false` otherwise
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**Implementation Details:**
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- Returns `false` immediately if `obj` is `null` or `undefined`
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- Checks that `obj.constructor` exists and is not `null`
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- Verifies that `obj.constructor.isBuffer` is a function
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- Calls `obj.constructor.isBuffer(obj)` to perform the actual Buffer check
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- Works with both Node.js Buffer and browserify Buffer implementations
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**Supported Buffer Types:**
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- `Buffer.from()` - Creates Buffer from various sources
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- `Buffer.alloc()` - Creates zero-filled Buffer of specified size
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- `Buffer.allocUnsafeSlow()` - Creates uninitialized Buffer
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- Any object with a constructor implementing the `isBuffer` method
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**Non-Buffer Types (returns false):**
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- Primitive types: `undefined`, `null`, `string`, `number`, `boolean`
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- Objects: `{}`, `[]`, functions
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- Objects with malformed `isBuffer` properties