How to do tree-shaking of aws-sdk?

[Kelvijn]

Dear devs,

How to use tree shaking?
I tried with TransformOptions but I cannot import this from the '@mrgrain/cdk-esbuild' package, which I found in https://constructs.dev/packages/@mrgrain/cdk-esbuild/v/2.0.0-alpha.1#mrgraincdkesbuildtransformoptions

My lambda currently is 500k lines long.

Kind regards,
Kelvijn

[mrgrain]

TransformOptions is only used for inline code, which only allows 4kb of code. You probably want to use TypeScriptCode or JavaScriptCode which uses BuildOptions.

According to esbuild docs, tree-shaking is only enabled either when bundling is enabled or when the output format is set to iife. But can be force-enabled by setting the respective option:

import * as lambda from "@aws-cdk/aws-lambda";
import { TypeScriptCode } from "@mrgrain/cdk-esbuild";

const bundledCode = new TypeScriptCode("src/index.ts", {
  buildOptions: {
    bundle: true, // or
    treeShaking: true,
  }
});

const fn = new lambda.Function(stack, "MyFunction", {
  runtime: lambda.Runtime.NODEJS_14_X,
  handler: "index.handler",
  code: bundledCode,
});

Please let me know if that works for you!

It also should work with InlineTypeScriptCode, if you really have to:

new InlineTypeScriptCode("const code: number = 1 + 2;", {
  buildOptions: {
    treeShaking: true,
  },
});

See:
https://constructs.dev/packages/@mrgrain/cdk-esbuild/v/2.0.0-alpha.1#mrgraincdkesbuildbuildoptionspropertybundle
https://constructs.dev/packages/@mrgrain/cdk-esbuild/v/2.0.0-alpha.1#mrgraincdkesbuildbuildoptionspropertytreeshaking

[Kelvijn]

Thank you for your quick response!!!

I will check later today or tomorrow.

[Kelvijn]

My cdk.out assets for the lambdas are still huge. (I also tried both options seperatly)
I have one package.json that all of my lambda's use.

My imports for CreateSession.ts :
import { v4 as uuidv4 } from 'uuid'
import * as AWS from 'aws-sdk'
import { makeHandler } from '../utils'

I haven't looked into lambda layers yet, because now all my node modules are packages in every lambda and maybe it is not possible to apply treeshaking in this setup.

[mrgrain]

Ah yes, I see. This will be because of this: import * as AWS from 'aws-sdk'

Long story short, esbuild doesn't know what parts of the SDK to "shake". You will have to change how you import aws-sdk. AWS has written a good blog post about this: https://aws.amazon.com/blogs/developer/modular-packages-in-aws-sdk-for-javascript/

E.g. to use S3 you will have to write

import S3 from "aws-sdk/clients/s3";

instead.

---

Alternatively, because you're creating a Lambda, you can mark aws-sdk as external und fallback to the version that comes pre-installed on Lambda:

new TypeScriptCode("./src/index.tsx", {
  buildOptions: {
    external: ["aws-sdk"],
  },
});

[Kelvijn]

I reduced the size of my lambdas to 1/10th by using the new V3 modular API that you suggested.

Thanks!!

Also great job with this library, makes bundling lambdas EZ!

[mrgrain]

Ah yes, I see. This will be because of this: import * as AWS from 'aws-sdk'

Long story short, esbuild doesn't know what parts of the SDK to "shake". You will have to change how you import aws-sdk. AWS has written a good blog post about this: https://aws.amazon.com/blogs/developer/modular-packages-in-aws-sdk-for-javascript/

E.g. to use S3 you will have to write

import S3 from "aws-sdk/clients/s3";

instead.

---

Alternatively, because you're creating a Lambda, you can mark aws-sdk as external und fallback to the version that comes pre-installed on Lambda:

new TypeScriptCode("./src/index.tsx", {
  buildOptions: {
    external: ["aws-sdk"],
  },
});