Node.js 4.x: What's New, Release History & Support Lifecycle

What Is New in Node.js 4?

The Merger of io.js and Node.js -- A New Chapter

Node.js 4 is the result of merging the io.js project back into Node.js under the io.js Technical Steering Committee. io.js was a community-led fork started in 2014 to accelerate v8 updates and open governance. The merger under the Node.js Foundation united both communities under a single, faster-moving release cadence.

This release ships V8 4.5 -- bringing a massive ES6 feature set natively. Before this, developers depended on Babel or CoffeeScript for class syntax, arrow functions, and template literals.

ES6 in Production -- Arrow Functions, Classes, Promises

Node.js 4 is the first release where writing modern JavaScript without a transpiler became viable for production server code. Key ES6 features enabled by default:

// Arrow functions
const add = (a, b) => a + b;

// Classes
class EventEmitter {
  constructor() { this.events = {}; }
  on(name, fn) { (this.events[name] = this.events[name] || []).push(fn); }
}

// Template literals
const msg = `Hello, ${user.name}! You have ${count} messages.`;

// Generators
function* range(start, end) {
  for (let i = start; i < end; i++) yield i;
}

// Promises
fetch('/api/data')
  .then(res => res.json())
  .catch(console.error);

Long-Term Support (LTS) Plan

Node.js 4 introduces the LTS lifecycle model. Even-numbered major versions (4, 6, 8...) become LTS releases, supported for 30 months -- 18 months active + 12 months maintenance. Odd-numbered versions are short-lived Current releases for new feature development.

This gives teams a predictable upgrade path: LTS to LTS, with ample overlap time. Node.js 4 is the first LTS under this model.

ARM Support -- Node.js on IoT and Embedded Devices

Node.js 4 adds first-class ARM support across ARMv6 (Raspberry Pi), ARMv7, and the new 64-bit ARMv8. Prebuilt binaries are available for all three. This unlocks Node.js as a platform for IoT and edge computing devices.