## What this fixes
Running cdk synth on an Amazon Linux 2 CodeBuild image started failing with SyntaxError: Unexpected token '?', pointing at the compiled aws-cdk CLI JavaScript. Nothing in the project had changed; the install step just pulled the newest aws-cdk. The cause was that aws-cdk 2.28.0 raised its Node requirement to >= 14.15.0 (it uses the ?? operator), while the Amazon Linux 2 build images only ship Node 12, and the ARM images had no newer option at all.
## The fix
aws-cdk 2.28.0 and later require Node.js 14.15.0 or newer, which the Amazon Linux 2 CodeBuild images do not provide. The verified workaround is to install a newer Node in the build's install phase with the n version manager, e.g. add an install command like n 16.15.1 before running cdk commands. The reporter confirmed this unblocked their pipeline. Longer term, move to a CodeBuild image with a newer Node runtime.
Source: https://github.com/aws/aws-cdk/issues/20739
## Why it happens
The thread above nails the cause, so the fix addresses that directly rather than symptoms. Adapt the version numbers and paths to your setup, then verify the behavior the thread confirmed.
## Source
https://github.com/aws/aws-cdk/issues/20739