SDK consumers using an older esbuild version for bundling results in a runtime error

[peter-at-work]

When AWS recently dropped support for node v16 starting with v3.723.0, the @aws-sdk/client-s3 package (and potentially other clients) has more efficient code, like static class initializers.

For example, the cjs module for S3ExpressIdentityCache.ts (v3.723.0+) contains the following:

// src/s3-express/classes/S3ExpressIdentityCache.ts
var S3ExpressIdentityCache = class _S3ExpressIdentityCache {
  constructor(data = {}) {
    this.data = data;
  }
  static {
    __name(this, "S3ExpressIdentityCache");
  }
...

An older version of the esbuild bundler would incorrectly generate code for static initializers like:

...,xs,v2=(xs=class{constructor(t={}){this.data=t}static{Le(xs,"S3ExpressIdentityCache")}...

Usage of the xs variable in the generated bundle is incorrect, and would exhibit a runtime error:

"TypeError: Object.defineProperty called on non-object",
        "    at defineProperty (<anonymous>)",
        "    at Le (/var/task/index.js:49:3176)",
        "    at <static_initializer> (/var/task/index.js:49:7213)",
        "    at /var/task/index.js:49:7166",
        "    at /var/task/index.js:1:340",
        "    at /var/task/index.js:76:44885",
        "    at /var/task/index.js:1:340",
        "    at Object.<anonymous> (/var/task/index.js:142:5100)",
        "    at Module._compile (node:internal/modules/cjs/loader:1469:14)",
        "    at Module._extensions..js (node:internal/modules/cjs/loader:1548:10)"

This has been fixed in esbuild v0.21.2 or later https://github.com/evanw/esbuild/releases/tag/v0.21.2 to generate code like:

...,c8=class l8{constructor(t={}){this.data=t}static{Le(this,"S3ExpressIdentityCache")}...

If you had been using an older version of esbuild for bundling, as described at https://aws.amazon.com/blogs/compute/optimizing-node-js-dependencies-in-aws-lambda/, then make sure you upgrade to v0.21.2 or later version of esbuild.