A good datetime formatter Curry Example

DateTimeFormatter.js

// Helper function to curry 2 arg functions
const curry = f => b => a => f(a,b);

// oh look, a 2 arg function!
function formatDateForLabeling(dateString, format='yyyymmdd') {
  let d = new Date(0);
  d.setUTCSeconds(dateString);
  if(format === 'mmddyyyy') {
    return new Intl.DateTimeFormat('en-US', {timeZone: 'UTC'}).format(d);
  }
  else if(format === 'ddmmyyyy') {
    return new Intl.DateTimeFormat('en-GB', {timeZone: 'UTC'}).format(d); // UTC ex: '24/9/2020'
  }
  else if(format === 'yyyymmdd') {
    return d.toISOString().split('T')[0]
  }
}


let dateFormat = 'yyyymmdd'; //'ddmmyyyy';
let UTCexample = 1586773746;

const curriedFormatDateForLabeling = curry(formatDateForLabeling);
const simpleFormatDate = curriedFormatDateForLabeling(dateFormat)

console.log(simpleFormatDate(UTCexample))