Release Notes for Node.js 16

Red Hat build of Node.js runs on a FIPS-enabled RHEL system and uses FIPS-certified libraries that are provided by RHEL.

The V8 JavaScript engine has been upgraded to v9.4.

The engine contains new features such as the ECMAScript RegExp Match Indices, which provides the start and end indices of captured strings in regular expression matches. The indices array is accessible by using the .indices property on match objects when the regular expression contains the /d flag. For example:

> const matchObj = /(Java)(Script)/d.exec('JavaScript');
undefined
> matchObj.indices
[ [ 0, 10 ], [ 0, 4 ], [ 4, 10 ], groups: undefined ]
> matchObj.indices[0]; // Match
[ 0, 10 ]
> matchObj.indices[1]; // First capture group
[ 0, 4 ]
> matchObj.indices[2]; // Second capture group
[ 4, 10 ]

The upgraded V8 JavaScript engine also provides the following JavaScript language features:

For more information about the changes that are available in the V8 JavaScript Engine, see the V8 blog.

The Timers Promises API is a new stable feature in Node.js 16 LTS.

The Timers Promises API provides an alternative set of timer functions that return Promise objects. This API removes the need to use util.promisify(). For example:

import { setTimeout } from 'timers/promises';
async function run() {
  await setTimeout(5000);
  console.log('Hello, World!');
}
run();

You can add metering labels to your Node.js pods and check Red Hat subscription details with the OpenShift Metering Operator.

Since their introduction in the Node.js 14 LTS release, the Node.js metering labels for OpenShift have been modified.

Node.js 16 LTS uses the following updated metering labels:

See Metering documentation for more information.

For more information on labels, see Understanding how to update labels on nodes.

This release of Red Hat build of Node.js is also certified for use on Red Hat Enterprise Linux 9.

Red Hat now provides a series of container images for the Red Hat build of Node.js 16 LTS release that are certified for use on Red Hat Enterprise Linux 9. You can use these container images to build and run Node.js applications on Red Hat Enterprise Linux 9 hosts. For more information about the certified container images, see Release Components.

For a number of core modules, this release includes the runtime deprecation of access to the process.binding() function. For example: process.binding(‘http_parser’)

The Node.js metering labels for OpenShift, which were originally introduced in the Node.js 14 LTS release, are now superseded by a newer set of metering labels.

The following Node.js metering labels are deprecated in this release:

The Web Crypto API is an implementation of the standard W3C Web Cryptography API. The Web Crypto API is accessible by using the require('crypto').webcrypto statement. For example:

const { subtle } = require('crypto').webcrypto;

(async function() {

  const key = await subtle.generateKey({
    name: 'HMAC',
    hash: 'SHA-256',
    length: 256
  }, true, ['sign', 'verify']);

  const digest = await subtle.sign({
    name: 'HMAC'
  }, key, 'I love cupcakes');

})();

The Web Streams API is an implementation of the WHATWG Streams Standard for handling streaming data. Because it is experimental, the Web Streams API is not exposed on the global object in this release. The Web Streams API is only accessible by using the new stream/web core module. For example:

import { ReadableStream, WritableStream } from 'stream/web';
// Or from 'node:stream/web'

The ESM Loader Hooks API consolidates ECMAScript modules (ESM) loader hooks to represent the steps that are needed to facilitate future loader chaining:

For consistency, the getGlobalPreloadCode loader hook has been renamed globalPreload.

Any loader that exports one or more obsolete hooks will trigger a single deprecation warning that lists the errant hooks.

The Blob class encapsulates immutable, raw data that can be safely shared across multiple worker threads.

Blob is a subclass of the Buffer class.

The node:test module facilitates the creation of JavaScript tests that report results in Test Anything Protocol (TAP) format.

To import the test runner module, use the following syntax:

import test from 'node:test';

The following code shows an example implementation of a parent test with two subtests:

test('top level test', async (t) => {
  await t.test('subtest 1', (t) => {
    assert.strictEqual(1, 1);
  });

  await t.test('subtest 2', (t) => {
    assert.strictEqual(2, 2);
  });
});

For more information, see the Node.js Test Runner documentation.