is-buffer

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.

Package Information

• Package Name: is-buffer
• Package Type: npm
• Language: JavaScript (with TypeScript definitions)
• Installation: npm install is-buffer

Core Imports

const isBuffer = require('is-buffer');

For ESM:

import isBuffer from 'is-buffer';

For TypeScript:

import isBuffer = require('is-buffer');
// or modern syntax:
import isBuffer from 'is-buffer';

Basic Usage

const isBuffer = require('is-buffer');

// Check various types
console.log(isBuffer(Buffer.from('hello')));     // true
console.log(isBuffer(Buffer.alloc(4)));          // true
console.log(isBuffer('string'));                 // false
console.log(isBuffer(null));                     // false
console.log(isBuffer({}));                       // false

Capabilities

Buffer Detection

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.

/**
 * Determine if an object is a Buffer
 * @param obj - The object to test
 * @returns true if the object is a Buffer, false otherwise
 */
function isBuffer(obj: any): boolean;

Parameters:

• obj (any): The object to test for Buffer instance

Returns:

• boolean: true if the object is a Buffer, false otherwise

Implementation Details:

• Returns false immediately if obj is null or undefined
• Checks that obj.constructor exists and is not null
• Verifies that obj.constructor.isBuffer is a function
• Calls obj.constructor.isBuffer(obj) to perform the actual Buffer check
• Works with both Node.js Buffer and browserify Buffer implementations

Supported Buffer Types:

• Buffer.from() - Creates Buffer from various sources
• Buffer.alloc() - Creates zero-filled Buffer of specified size
• Buffer.allocUnsafeSlow() - Creates uninitialized Buffer
• Any object with a constructor implementing the isBuffer method

Non-Buffer Types (returns false):

• Primitive types: undefined, null, string, number, boolean
• Objects: {}, [], functions
• Objects with malformed isBuffer properties