SlowBuffer to Buffer.allocUnsafeSlow

Migrate deprecated SlowBuffer constructor to Buffer.allocUnsafeSlow() for Node.js DEP0030

This codemod migrates deprecated SlowBuffer usage to Buffer.allocUnsafeSlow() to handle Node.js DEP0030.

What It Does

This codemod transforms:

1. SlowBuffer constructor calls to Buffer.allocUnsafeSlow()
2. Direct SlowBuffer calls to Buffer.allocUnsafeSlow()
3. Import/require statements to use Buffer instead of SlowBuffer

Before/After

ESM

Before:

import { SlowBuffer } from "buffer";
const buf = new SlowBuffer(1024);

After:

import { Buffer } from "buffer";
const buf = Buffer.allocUnsafeSlow(1024);

CommonJS

Before:

const { SlowBuffer } = require("buffer");
const buf = new SlowBuffer(1024);

After:

const { Buffer } = require("buffer");
const buf = Buffer.allocUnsafeSlow(1024);

The SlowBuffer constructor was deprecated in Node.js v6.0.0 and removed in later versions. This migration is essential for maintaining compatibility with modern Node.js versions.

Usage

Run this codemod on your project:

npx codemod node/userland/slow-buffer-to-buffer-alloc-unsafe-slow

Buffer.allocUnsafeSlow() creates a buffer outside the shared internal memory pool. Use this when you need a buffer that won’t be pooled, but remember that the buffer contents are uninitialized and may contain sensitive data.

Related Deprecations

• DEP0030: SlowBuffer