How to find the earliest date in an array using JavaScript

Question

How can I find the earliest date, i.e. minimum date, in an array using JavaScript?

Example:

["10-Jan-2013", "12-Dec-2013", "1-Sep-2013", "15-Sep-2013"]

My output should be:

["10-Jan-2013", "1-Sep-2013", "15-Sep-2013", "12-Dec-2013"]

How can I do this?

Answer 1

I'd suggest passing an anonymous function to the sort() method:

var dates = ['10-Jan-2013','12-Dec-2013','1-Sep-2013','15-Sep-2013'],
    orderedDates = dates.sort(function(a,b){
        return Date.parse(a) > Date.parse(b);
    });

console.log(orderedDates); // ["10-Jan-2013", "1-Sep-2013", "15-Sep-2013", "12-Dec-2013"]

var dates = ['10-Jan-2013', '12-Dec-2013', '1-Sep-2013', '15-Sep-2013'],
  orderedDates = dates.sort(function(a, b) {
    return Date.parse(a) > Date.parse(b);
  });

console.log(orderedDates);

JS Fiddle demo.

Note the use of an array ['10-Jan-2013','12-Dec-2013','1-Sep-2013','15-Sep-2013'] of quoted date-strings.

The above will give you an array of dates, listed from earliest to latest; if you want only the earliest, then use orderedDates[0].

A revised approach, to show only the earliest date – as requested in the question – is the following:

var dates = ['10-Jan-2013', '12-Dec-2013', '1-Sep-2013', '15-Sep-2013'],
    earliest = dates.reduce(function (pre, cur) {
        return Date.parse(pre) > Date.parse(cur) ? cur : pre;
    });

console.log(earliest); // 10-Jan-2013

var dates = ['10-Jan-2013', '12-Dec-2013', '1-Sep-2013', '15-Sep-2013'],
  earliest = dates.reduce(function(pre, cur) {
    return Date.parse(pre) > Date.parse(cur) ? cur : pre;
  });

console.log(earliest);

JS Fiddle demo.

References:

• Date.parse().
• Array.prototype.reduce().
• Array.prototype.sort().