We are excited to announce that you can now develop AWS Lambda functions using the Node.js 12.x runtime, which is the current Long Term Support (LTS) version of Node.js. Start using this new version today by specifying a runtime parameter value of nodejs12.x when creating or updating functions.

Language Updates

Here is a quick primer that highlights just some of the new or improved features that come with Node.js 12:

Updated V8 engine

Public class fields

Private class fields

TLS improvements

Updated V8 engine

Node.js 12.x is powered by V8 7.4, which is a significant upgrade from V8 6.8 powering the previous Node.js 10.x. This upgrade brings with it performance improvements for faster JavaScript execution, better memory management, and broader support for ECMAScript.

Public class fields

With the upgraded V8 version comes support for public class fields. This enhancement allows for public fields to be defined at the class level, providing cleaner code.

Before:

class User { constructor(user){ this.firstName = user.firstName this.lastName = user.lastName this.id = idGenerator() } }

After:

{ id = idGenerator() constructor(user){ this.firstName = user.firstName this.lastName = user.lastName } }

Private class fields

In addition to public class fields, Node.js also supports the use of private fields in a class. These fields are not accessible outside of the class and will throw a SyntaxError if an attempt is made. To mark a field as private in a class simply start the name of the field with a ‘#’.

class User { #loginAttempt = 0; increment() { this.#loginAttempt++; } get loginAttemptCount() { return this.#loginAttempt; } } const user = new User() console.log(user.loginAttemptCount) // returns 0 user.increment() console.log(user.loginAttemptCount) // returns 1 console.log(user.#loginAttempt) // returns SyntaxError: Private field '#loginAttempt' // must be declared in an enclosing class

TLS improvements

As a security improvement, Node.js 12 has also added support for TLS 1.3. This increases the security of TLS connections by removing hard to configure and often vulnerable features like SHA-1, RC4, DES, and AES-CBC. Performance is also increased because TLS 1.3 only requires a single round trip for a TLS handshake compared to earlier versions requiring at least two.

For more information, see the AWS Lambda Developer Guide.

Runtime Updates

Multi-line log events in Node.js 12 will work the same way they did in Node.js 8.10 and before. Node.js 12 will also support exception stack traces in AWS X-Ray helping you to debug and optimize your application. Additionally, to help keep Lambda functions secure, AWS will update Node.js 12 with all minor updates released by the Node.js community.

Deprecation schedule

AWS will be deprecating Node.js 8.10 according to the end of life schedule provided by the community. Node.js 8.10 will reach end of life on December 31, 2019. After January 6, 2020, you can no longer create a Node.js 8.10 Lambda function and the ability to update will be disabled after February 3, 2020. More information on can be found here.

Existing Node.js 8.10 functions can be migrated to the new runtime by making any necessary changes to code for compatibility with Node.js 12, and changing the function’s runtime configuration to “nodejs12.x”. Lambda functions running on Node.js 12 will have 2 full years of support.

Amazon Linux 2

Node.js 12, like Node.js 10, Java 11, and Python 3.8, is based on an Amazon Linux 2 execution environment. Amazon Linux 2 provides a secure, stable, and high-performance execution environment to develop and run cloud and enterprise applications.

Next steps

Get started building with Nodejs 12 today by specifying a runtime parameter value of nodejs12.x when creating or updating your Lambda functions.

Happy coding with Nodejs 12!