TypeScript, AWS SAM and Rollup.js

This time we are using Rollup instead of Webpack and it is super easy. Also it requires less configuration.

Before going further I suggest you read the other blog post which will explain the conventions behind the Rollup configuration.

Rollup Configuration

// rollup.config.js
import fs from 'fs'
import CloudFormation from 'yaml-cfn'
import typescript from 'rollup-plugin-typescript'
import nodeResolve from 'rollup-plugin-node-resolve'
const defaultConfig = {
  plugins: [
    nodeResolve(),
    typescript(),
  ],
output: {
    format: 'commonjs',
  },
external: [
    'aws-sdk',
  ],
}
const { Resources } = CloudFormation.yamlParse(fs.readFileSync('template.yml'))
const entries = Object.values(Resources)
  .filter(resource => resource.Type == 'AWS::Serverless::Function')
  .filter(resource => resource.Properties.Runtime.startsWith('nodejs'))
.map(resource => {
    const file = resource.Properties.Handler.split('.')[0]
    const prefix = resource.Properties.CodeUri.substr(8)
return Object.assign({}, defaultConfig, {
      input: `${prefix}/${file}.ts`,
output: {
        format: 'cjs',
        dir: `.rollup/${prefix}`,
      }
    })
  })
export default entries

AWS SAM Template

AWSTemplateFormatVersion: '2010-09-09'
Transform: 'AWS::Serverless-2016-10-31'
Resources:
  MyFunction:
    Type: 'AWS::Serverless::Function'
    Properties:
      Handler: index.handler
      Runtime: nodejs10.x
      CodeUri: .rollup/packages/my-function

Result

$ yarn rollup -c rollup.config.js
packages/my-function/index.ts → .rollup/packages/my-function...
created .rollup/packages/my-function in 283ms

When developing you would want to start it in watch mode with --watch. Then you can always use sam local invoke as normal.