Sandbox function deployment does not compile TS into JS

[rpostulart]

Environment information

System:
  OS: macOS 14.6.1
  CPU: (16) x64 Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
  Memory: 37.20 MB / 16.00 GB
  Shell: /bin/zsh
Binaries:
  Node: 22.2.0 - /usr/local/bin/node
  Yarn: undefined - undefined
  npm: 10.7.0 - /usr/local/bin/npm
  pnpm: undefined - undefined
NPM Packages:
  @aws-amplify/auth-construct: 1.2.2
  @aws-amplify/backend: 1.1.1
  @aws-amplify/backend-auth: 1.1.2
  @aws-amplify/backend-cli: 1.2.3
  @aws-amplify/backend-data: 1.1.1
  @aws-amplify/backend-deployer: 1.0.5
  @aws-amplify/backend-function: 1.3.2
  @aws-amplify/backend-output-schemas: 1.2.0
  @aws-amplify/backend-output-storage: 1.1.1
  @aws-amplify/backend-secret: 1.0.1
  @aws-amplify/backend-storage: 1.1.1
  @aws-amplify/cli-core: 1.1.2
  @aws-amplify/client-config: 1.2.0
  @aws-amplify/deployed-backend-client: 1.4.0
  @aws-amplify/form-generator: 1.0.1
  @aws-amplify/model-generator: 1.0.4
  @aws-amplify/platform-core: 1.0.6
  @aws-amplify/plugin-types: 1.2.1
  @aws-amplify/sandbox: 1.1.3
  @aws-amplify/schema-generator: 1.2.1
  aws-amplify: 6.5.1
  aws-cdk: Not Found
  aws-cdk-lib: 2.152.0
  typescript: 5.5.4
AWS environment variables:
  AWS_STS_REGIONAL_ENDPOINTS = regional
  AWS_NODEJS_CONNECTION_REUSE_ENABLED = 1
  AWS_SDK_LOAD_CONFIG = 1
No CDK environment variables

Describe the bug

When I add a custom resource Lambda function and I would like to code this with Typescript. Then when saving the file a new trigger starts deploying, which is fine, but it does not compiles TS into JS in the lambda function. So I need to do this locally first and this triggers a new deployment again.

Can sandbox deployment automaticly compile ts into js during deployment

Reproduction steps

npx ampx sandbox

[ykethan]

Hey @rpostulart, thank you for reaching out. Is the custom resource a Lambda function created using the CDK Lambda construct?
The Lambda NodeJS construct should provide this capability of automatic transpiling and bundling of TypeScript or Javascript code.
But curious on the use case for creating a custom lambda function as Amplify Gen 2 defineFunction already utilizes Lambda NodeJS construct to create the function.

[rpostulart]

Yes, this is the code which is created with CDK and imported as target for the eventbridge event which are also defined as CDK

import * as cdk from "aws-cdk-lib";
import * as lambda from "aws-cdk-lib/aws-lambda";
import { Construct } from "constructs";

import * as iam from "aws-cdk-lib/aws-iam";

export class MailService extends Construct {
  public readonly lambdaFunction: lambda.Function;

  constructor(scope: Construct, id: string) {
    super(scope, id);

    // Define Lambda function
    this.lambdaFunction = new lambda.Function(this, "MailService", {
      runtime: lambda.Runtime.NODEJS_20_X,
      code: lambda.Code.fromAsset(
        "amplify/custom/services/mailService/src/src/"
      ),
      handler: "index.handler",
    });

    // Grant SES permissions (if needed)
    this.lambdaFunction.addToRolePolicy(
      new iam.PolicyStatement({
        effect: iam.Effect.ALLOW,
        actions: ["ses:SendEmail", "ses:SendRawEmail"],
        resources: ["*"], // You might want to restrict this to specific SES ARNs
      })
    );
  }
}

[ykethan]

Hey @rpostulart, thank you for info is this a scheduled event or is this triggered by an AWS event? If this is a AWS event what service triggers this event?
The existing defineFunction does support scheduled functions, refer to scheduling functions documentation

[rpostulart]

This is indeed a scheduled event and targeted lambda by event bridge

[ykethan]

@rpostulart thanks for the information, the NodejsFunction construct should help with your use case to transpile automatically.