How to handle ISO date strings in TypeScript?

Question

I\'m brand new to typescript, so I\'m trying to get the hang of it.

A network request is going to return a JSON object with a field in ISO Date string format.

Answer 1

You can use a Type Guard.

import moment from 'moment'

export const isISO = (input: any): input is tISO =>
  moment(input, moment.ISO_8601, true).isValid()

Then you can use whatever custom logic in your you want to handle any bad dates, e.g.:

const maybeISO = fetch('Maybe ISO')

if (isISO(maybeISO)) {
  // proceed
} else {
  // check other format?
  // log error?
}

Cheers.