buffer.atob() & buffer.btoa() Migration

Migrate from legacy buffer.atob() and buffer.btoa() APIs to modern Buffer methods for base64 encoding and decoding

This recipe migrates usage of the legacy buffer.atob() and buffer.btoa() APIs to the current recommended Buffer-based approaches for base64 encoding and decoding.

What It Does

The codemod transforms:

• buffer.atob(data) → Buffer.from(data, 'base64').toString('binary')
• buffer.btoa(data) → Buffer.from(data, 'binary').toString('base64')

Usage

npx codemod nodejs/buffer-atob-btoa

Examples

Migrating buffer.atob()

Decoding base64-encoded data:

Before

const buffer = require('node:buffer');
const data = 'SGVsbG8gV29ybGQh'; // "Hello World!" in base64
const decodedData = buffer.atob(data);
console.log(decodedData); // Outputs: Hello World!

Migrating buffer.btoa()

Encoding data to base64:

Before

const buffer = require('node:buffer');
const data = 'Hello World!';
const encodedData = buffer.btoa(data);
console.log(encodedData); // Outputs: SGVsbG8gV29ybGQh

Why Migrate?

The buffer.atob() and buffer.btoa() methods were convenience wrappers around Buffer operations. Using Buffer methods directly:

• Provides more explicit control over encoding
• Aligns with modern Node.js best practices
• Reduces dependency on the buffer module import
• Offers better performance in some scenarios

The Buffer API provides more encoding options beyond ‘base64’ and ‘binary’, including ‘hex’, ‘utf8’, ‘ascii’, and more.

References

• Node.js Buffer Documentation