How to create an hours + minutes array with moment.js and ES6?

user_5074921 0
Viewed 7132

I'm trying to create an array of hours in a day with 30 minute intervals with moment.js and ES6.

Example: let hours = ["12:00 AM", "12:30 AM", "1:00 AM", "1:30 AM", ..., "11:30 PM"]

I already have this for function:

someFunction () {
  const items = []
  for (let hour = 0; hour < 24; hour++) {
    items.push(moment({ hour }).format('h:mm A'))
    items.push(moment({ hour, minute: 30 }).format('h:mm A'))
  }
  return items
}

But I would like to make it more ES6-like.

I have gotten this far:

someFunction () {
  let timeSlots = new Array(24).fill().map((acc, index) => {
    let items = []
    items.push(moment( index ).format('h:mm A'))
    items.push(moment({ index, minute: 30 }).format('h:mm A'))
  })
  return timeSlots
}

But it outputs:

["1:00 AM", "12:30 AM", "1:00 AM", "12:30 AM", "1:00 AM", "12:30 AM", "1:00 AM", "12:30 AM", "1:00 AM", "12:30 AM", "1:00 AM", "12:30 AM", ...]

momentjs ecmascript-6 javascript
7 Answers
function someFunction () {
  const items = [];
  new Array(24).fill().forEach((acc, index) => {
    items.push(moment( {hour: index} ).format('h:mm A'));
    items.push(moment({ hour: index, minute: 30 }).format('h:mm A'));
  })
  return items;
}
user_19236260

You can use array#from with array#reduce to generate 30 minutes interval time.

let someFunction = () => {
  return Array.from({length: 24}, (_,i) => i).reduce((r,hour) => {
     r.push(moment({hour, minute: 0}).format('h:mm A'));
     r.push(moment({hour, minute: 30}).format('h:mm A'));
     return r;
  }, []);
}
console.log(someFunction());
<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.22.2/moment.min.js"></script>

user_47584940

here is working code:

someFunction = () => {
  var items = []
  var currentDate = moment('12');
  new Array(48).fill().map((acc, index) => {
    items.push(currentDate.format('h:mm A'))
    currenDate = currentDate.add(30, 'minutes');
  })
  return items
}

console.log(someFunction());

Working fiddle: http://jsfiddle.net/ekqxhwf4/1/

user_85261410

You could use Array.from method to generate 2d array and then concat with spread syntax to create 1d array.

function create () {
  return [].concat(...Array.from(Array(24), (_, hour) => ([
    moment({hour}).format('h:mm A'),
    moment({ hour, minute: 30 }).format('h:mm A')
  ])))
}

console.log(create())
<script src="http://momentjs.com/downloads/moment.js"></script>

user_46207710

I know momentJS was a requirement, but could also be easily solved with ordinary JavaScript Date objects:

function everyXMilliseconds(x) {
  if (x === void 0) {
    x = 86400000;
  }
  var base = new Date(86400000);
  var currentDate = new Date(86400000);
  var dates = [];
  while (currentDate.getUTCDate() === base.getUTCDate()) {
    dates.push(new Date(currentDate.getTime()));
    currentDate.setTime(currentDate.getTime() + x);
  }
  return dates;
}

function everyXSeconds(x) {
  if (x === void 0) {
    x = 86400;
  }
  return everyXMilliseconds(x * 1000);
}

function everyXMinutes(x) {
  if (x === void 0) {
    x = 1440;
  }
  return everyXSeconds(x * 60);
}

function everyXHours(x) {
  if (x === void 0) {
    x = 24;
  }
  return everyXMinutes(x * 60);
}
//Offsets date with its own timezone difference
function toLocalTime(date) {
  date.setUTCHours(date.getUTCHours() + date.getTimezoneOffset() / 60);
  return date;
}
//TEST
//get dates
var dates = everyXHours(0.5);
// dates to time
console.log('UTC times', dates.map(function(d) {
  return d.toLocaleTimeString("uk");
}));
// dates to time localized
console.log('Local times', dates.map(toLocalTime).map(function(d) {
  return d.toLocaleTimeString("uk");
}));

My snippet above is bit overly complicated, but it illustrates that you can make really flexible system without need to import libraries.

user_52427390

you can get the value with the label.

function someFunction () {
  const items = [];
  new Array(24).fill().forEach((acc, index) => {
    items.push({"value": moment( {hour: index} ).format('HH:mm'), "label": moment( {hour: index} ).format('h:mm A')});
    items.push({"value": moment({ hour: index, minute: 30 }).format('HH:mm'), "label": moment({ hour: index, minute: 30 }).format('h:mm A')});
  })
  return items;
}
user_127153420

An even shorter version would be:

const someFunction = () => 
  Array(48)
    .fill()
    .map((_, index) =>
      moment({
        hour: Math.floor(0.5 * index),
        minute: 30 * (index % 2)
      })
      .format("h:mm A"));
user_47526320
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