feat: dual module export

[antstanley]

This PR adds dual CommonJS and ES Module support to DynamoDB Toolbox.

Issue it resolves: #606

The changes include the following

• Update package.json to include exports property to define location to be used for ES imports

"exports": {
    ".": {
      "import": {
        "default": "./dist/esm/index.js",
        "types": "./dist/esm/index.d.ts"
      },
      "require": {
        "default": "./dist/cjs/index.js",
        "types": "./dist/cjs/index.d.ts"
      }
    }
  },

• Update package.json to set default module type to module

  "types": "module"

• Create a tsconfig.esm.json file with ES module specify TypeScript settings

• Rename tsconfig.build.json to tsconfig.cjs.json and add CommonJS setting for TypeScript

• Update root tsconfig.json to use ES modules by default

• Update all .ts files to use explicit .js imports in accordance with the ES Module spec and Node implementation. Reference https://www.totaltypescript.com/relative-import-paths-need-explicit-file-extensions-in-ecmascript-imports

• Rename jest.config.js to jest.config.cjs to explicitly set it to a CommonJS module as the package default is now module

• Update ts-jest config in jest.config.cjs to useESM: true and other ES module required config

• Update all test files to use explicit .js imports as required by ES module spec and Node implementation

• Add module declaration deep-copy.d.ts for the deep-copy module used by Entity, as it's existing declaration is not sufficient for ES modules

Apologies for the size of the PR. Unfortunately due to ES modules requiring explicit import of files by .js extensions I had to touch almost every file, but I only touched them gently.

The tests run and pass. I've also shipped a version of this to @antstanley/dynamodb-toolbox if you want to run it yourself and validate behaviour.

Bundling this version now enables me to use ES modules with DynamoDB Toolbox in my Lambda functions without bundling the AWS SDK v3.

One side effect I've noticed is the ES module version of DynamoDB Toolbox bundles more efficiently, dropping around 30Kb from my specific bundle.

[antstanley]

Missed two file extenstions on the test suite used for type checking. Updated and committed b74fd58

[naorpeled]

Just wondering,
why do we need this? deep-copy comes out of the box with type defs.
Not sure what I'm missing 🙏

[antstanley]

The type defs don't support ES modules. The export a function, not a module. ES modules require a module declaration for modules to be reference correctly.

The type def shipped looks like this

declare function dcopy<T>(arg: T): T

export default dcopy

with no module declaration

[naorpeled]

Oh, gotcha!

[naorpeled]

Hey @antstanley,
thanks for this!!! much appreciated 😎

You're awesome.

LGTM!

[antstanley]

Yay! I've recently gone on a mission to get all the packages I use to support dual modules so I can use ESM in Lambda.

Merging this saves me over a 1MB in my bundle size for one of my functions 1.2MB -> 200KB, mainly by enabling me to use ESM without bundling AWS SDK v3.

Thank you!

[naorpeled]

this is now available in v0.9.0 :)