Node.js Buffer for Browsers (ES6 Rewrite)

Common errors

• TypeError: Buffer is not a constructor

  cause Attempting to use `Buffer` as a constructor or class when it was imported incorrectly, often via a default import instead of a named export (ESM) or by destructuring `require('buffer-es6')` (CJS).
  fix For ESM, use `import { Buffer } from 'buffer-es6';`. For CJS, use `const Buffer = require('buffer-es6');`.

• Cannot find module 'buffer-es6'

  cause The `buffer-es6` package has not been installed, or the import path is incorrect.
  fix Run `npm install buffer-es6` or `yarn add buffer-es6`. Ensure the import path is exactly `'buffer-es6'` for both ESM and CJS.

• Cannot find module 'buffer'

  cause Attempting to import the core `buffer` module or the `buffer` npm package when `buffer-es6` is installed and the environment expects the specific `buffer-es6` module. This often happens due to confusion between the two packages.
  fix If intending to use `buffer-es6`, ensure all your import paths reference `'buffer-es6'`. If you truly need the main `buffer` npm package (which provides Node.js core-like Buffer behavior), install it with `npm install buffer` and adjust imports accordingly (e.g., `require('buffer/').Buffer` for CJS).

Warnings

• breaking In older browsers lacking Typed Array support (e.g., IE6-9), `buf.slice()` returns a new Buffer that does NOT share underlying memory with the original. Modifications to one will not affect the other, unlike Node.js behavior and modern browser implementations.
  Fix: For critical applications in very old browser environments, avoid relying on shared memory behavior of `slice()` or implement custom copying logic. This typically does not affect modern browsers.
• gotcha The `buffer-es6` package is a distinct npm package from the more commonly known `buffer` package. They have different installation commands (`npm install buffer-es6` vs `npm install buffer`) and different primary import paths. Confusing the two can lead to module not found errors or unexpected behavior.
  Fix: Always ensure you install `buffer-es6` if that is the intended package, and use `import { Buffer } from 'buffer-es6'` (ESM) or `const Buffer = require('buffer-es6')` (CJS) for correct imports.
• gotcha `buffer-es6` explicitly disables certain Node.js compatibility features present in the core `buffer` package. This was done to facilitate Rollup tree-shaking. While generally beneficial for bundle size, it might remove specific behaviors or polyfills expected in highly specialized or legacy contexts.
  Fix: Review the specific 'compatibility stuff' turned off by inspecting the `buffer-es6` source or consulting its documentation if you encounter unexpected behavior related to Buffer operations, especially when migrating from the standard `buffer` package.
• gotcha The bundled `base64-js` dependency, as mentioned in the README, has an 'MIT with no author listed' license attribution. While MIT is permissive, the lack of an author might be a concern for projects with strict license compliance requirements.
  Fix: If this is a legal concern, review the license information of `base64-js` within the `buffer-es6` package or consult legal counsel. Alternatively, consider using a different Buffer implementation if this specific licensing detail is problematic.

Install

• npm install buffer-es6 npm
• yarn add buffer-es6 yarn
• pnpm add buffer-es6 pnpm

Imports

• Buffer
  wrong:

  import Buffer from 'buffer-es6';

  correct:

  import { Buffer } from 'buffer-es6';

  For ES Modules, `Buffer` is a named export. Attempting a default import will result in a TypeError.
• Buffer
  wrong:

  const { Buffer } = require('buffer-es6');

  correct:

  const Buffer = require('buffer-es6');

  For CommonJS, the module directly exports the `Buffer` constructor. Destructuring `require('buffer-es6')` is incorrect.
• Buffer (alternative core Buffer package import)
  wrong:

  import { Buffer } from 'buffer';

  correct:

  const Buffer = require('buffer/').Buffer;

  This specific import path (`require('buffer/')`) is for the *main* `buffer` npm package, not `buffer-es6`. It is critical to distinguish between `buffer-es6` and the core `buffer` package, as they have different installation and import conventions. Confusion between the two is a common pitfall.

Quickstart

Demonstrates various fundamental Buffer operations including creation, writing, reading, concatenation, and type checking, using ES module syntax.

import { Buffer } from 'buffer-es6';

// Create a new Buffer of 10 bytes and fill it with zeros
const buf1 = Buffer.alloc(10);
console.log('Buffer 1 (alloc):', buf1.toString('hex'));

// Create a Buffer from a string, using UTF-8 encoding
const buf2 = Buffer.from('Hello Buffer!', 'utf8');
console.log('Buffer 2 (from string):', buf2.toString());

// Write data to an existing buffer
buf1.write('ABC', 0, 3, 'utf8');
console.log('Buffer 1 after write:', buf1.toString('utf8'));

// Concatenate two buffers
const buf3 = Buffer.concat([buf1, buf2]);
console.log('Buffer 3 (concat):', buf3.toString('utf8'));

// Check buffer length
console.log('Buffer 3 length:', buf3.length);

// Access individual bytes
console.log('Byte at index 1 of buf2:', buf2[1]); // Prints 'e' ASCII value

// Convert to JSON
const json = buf2.toJSON();
console.log('Buffer 2 as JSON:', json);

// Create a Buffer from a JavaScript ArrayBuffer
const arrayBuffer = new ArrayBuffer(5);
const uint8Array = new Uint8Array(arrayBuffer);
uint8Array[0] = 72; // 'H'
uint8Array[1] = 105; // 'i'
const buf4 = Buffer.from(arrayBuffer);
console.log('Buffer 4 (from ArrayBuffer):', buf4.toString());

// Check if a variable is a Buffer
console.log('Is buf1 a Buffer?', Buffer.isBuffer(buf1));
console.log('Is "Hello" a Buffer?', Buffer.isBuffer('Hello'));