sort array of objects by property in object

Question

I have an array of objects like:

[
 {date: "2016-01-07T15:01:51+00:00", text: "Lorem ipsum"}, 
 {date: "2016-22-08T15:04:36+00:00", text: "dolor"},
 // etc.
]

How's the best way to sort these by the date property? I'm already mapping this array to a react component, so any solution that works within the map function I guess would be preferred, but not essential.

I'm trying to use the sort() method at the moment, but can't work how to feed it the date property.

• georg: Since you have ISO dates, it's safe to compare them as strings, use date1.localeCompare(date2) in your sort callback.
• MinusFour: ^ arr.sort((a,b) => a.date.localeCompare(b.date))
• Vince: @sanjaypoyzer, unless it's a mistake in the formatting, "2016-22-08T15:04:36+00:00" is an invalid date format in javascript. Notice new Date("2016-22-08T15:04:36+00:00") outputs Invalid Date

Answer 1

You can have a custom sort function:

var data = [{
 date: "2016-07-01T15:01:51+00:00",
 text: "Lorem ipsum"
}, {
 date: "2016-02-22T15:04:36+00:00",
 text: "dolor"
}, {
 date: "2015-08-22T15:04:36+00:00",
 text: "test"
}]
var result = data.sort(function(a, b) {
 var date1 = new Date(a.date);
 var date2 = new Date(b.date);
 console.log(date1, date2);
 return (+date1 - +date2);
});
console.log(result)

• Rajesh Dixit: @georg, what is the difference between return (a-b) and return (a>b). Isn't sort considers -ve value as false and +ve value as true? I may be wrong. Just wanted to confirm.
• georg: You have to return -1, 0, or 1 from the sort callback, not true/false.
• suryanaga: @georg Thanks, what do the -1, 0, or 1 values correspond to?
• Rajesh Dixit: @sanjaypoyzer I guess less than, equal and greater than.
• georg: @sanjaypoyzer: when comparing a to b, return -1 (or any negative) if a < b, +1 (or any positive) if a > b, and 0 if they are equal, see developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/…