sample.js

// Main API Lambda

async function (event) {
  let input
  let context
  let response
  
  try {
    // input is simply the relevant input (not the whole 
    // AWS Lambda event which contains lots of unnecessary data)
    const input = getInputFromEvent(event)

    // Context will contain some useful info like user, requestId, etc.
    const context = getContextInfo(event)
    response = await doSomething(input)
    
    // Broadcast to an SNS Topic
    // publishToSNS is a wrapper function that publishes to SNS
    // the input, context, and response
    await publishToSNS(input, context, response)
  } catch (err) {
    throw new Error(err)
  }
  
  return response
}