Check if date is less than 1 hour ago?

Is there a way to check if a date is less than 1 hour ago like this?

// old date
var olddate = new Date("February 9, 2012, 12:15");

// current date
var currentdate = new Date();

if (olddate >= currentdate - 1 hour) {
    alert("newer than 1 hour");
else {
    alert("older than 1 hour");
}

Also, different question - is there a way to add hours to a date like this?

var olddate = new Date("February 9, 2012, 12:15") + 15 HOURS; // output: February 10, 2012, 3:15

Solution 1:

Define

var ONE_HOUR = 60 * 60 * 1000; /* ms */

then you can do

((new Date) - myDate) < ONE_HOUR

To get one hour from a date, try

new Date(myDate.getTime() + ONE_HOUR)                       

Solution 2:

Using some ES6 syntax:

const lessThanOneHourAgo = (date) => {
    const HOUR = 1000 * 60 * 60;
    const anHourAgo = Date.now() - HOUR;

    return date > anHourAgo;
}

Using the Moment library:

const lessThanOneHourAgo = (date) => {
    return moment(date).isAfter(moment().subtract(1, 'hours'));
}

Shorthand syntax with Moment:

const lessThanOneHourAgo = (date) => moment(date).isAfter(moment().subtract(1, 'hours'));

Solution 3:

the moment library can really help express this. The trick is to take the date, add time, and see if it's before or after now:

  lastSeenAgoLabel: function() {
    var d = this.lastLogin();
    if (! moment(d).isValid()) return 'danger';  // danger if not a date.
    if (moment(d).add(10, 'minutes').isBefore(/*now*/)) return 'danger'; // danger if older than 10 mins
    if (moment(d).add(5,  'minutes').isBefore(/*now*/)) return 'warning'; // warning if older than 5mins
    return 'success';  // Looks good!
  },