Tips on javascript / typescript development

Spread

Update object with spread operator

In React and React Native, the common patter is to map an object to form inputs and update the values of the properties. Spread operator, ..., comes really handy for the purpose.

<FloatingLabelInput
  isRequired
  label="Customer Address (line1)"
  defaultValue={job.customer.address.line1}
  errorMessage={validation.customerAddress1}
  onChangeText={(customerAddress1: string) => {
    setJob({
      ...job,
      customer: {
        ...job.customer,
        address: {
          ...job.customer.address,
          line1: customerAddress1.trim()
        }
      }
    })
    setValidation({...validation, customerAddress1: ''})
  }}
  autoCapitalize="none"
/>

Kill all node processes

Your old server processor is still running and when you do yarn stardt it asks if you want the new server run with a new port number, annoyingly. Kill all the existing node processes.

ps aux | grep node
killall -9 node

Promise

Create a promise from a non-async function

Sometimes, I have to do this to match the expected signature.

export const handler = startServerAndCreateLambdaHandler(
  server,
  handlers.createAPIGatewayProxyEventRequestHandler(),
  {
    middleware: [
      async event => {
        return new Promise(result => {
          console.log('event', event, result)
          result()
        })
      },
    ],
  }
)