index.ts

import * as lambdas from "./lambda";

const fn = new aws.lambda.CallbackFunction(`fn`, {
    callback: lambdas.handler,
    tags: standardTags,
    environment: {
        variables: {
            TABLENAME: infra.tableName
        }
    },
    runtime: aws.lambda.NodeJS12dXRuntime
})

lambda.ts

export const handler = (e) => {
    console.log(e);
};