Sort an array with objects date property

Question

I have an array with objects that looks like this:

{
 Title: "Title",
 Url: "myUrl",
 publishedDate: "19/01/2021"
  },
  {
   Title: "Title 2",
Url: "myUrl",
publishedDate: "17/12/2020"
  },
  {
  Title: "Title 3",
Url: "myUrl",
publishedDate: "11/03/2021"
  },
  {
Title: "Title 4",
Url: "myUrl",
publishedDate: "11/12/2020"
  }

I have saved them in my state (array).

this.state.data

I want to order the objects based on the property "publishedDate" (and without using the new Date() due to memory efficiency). I try:

console.log(this.state.data.sort(function(a, b) {
  var c = new Date(a.publishedDate);
  var d = new Date(b.publishedDate);
  return c.getTime() - d.getTime();
}))

But the objects are not in order. What is wrong in the code? Playground:

https://www.typescriptlang.org/play?#code/FAYw9gdgzgLgBAQwE5IQTzgXjgb2HOAEwRgQC44BtPOAFQEsYAbAUwoCIHmX2AafAKpImHALZohTPvgAOAVwBGTelAAWLQgBESbOOwCMATgD0ABn3GATKcv72+OAF9+BGgS6sOHlnEvTJYhLC0vJKKupaOhz6AOzG+pZWNqb2BM4Obt5ejKxwAMz+woGSIYrKahraMLoGFqZ5SbapTi64wFl63nAALIUieuIl-KHlEVU1+hYJjSkOjg4AusDzwKCQUGCsAHRMYADmABTIqGhbxKRbG0gwBwBmchAgMPSQR7xwCgCUbQQAbshwEBYOAQFgAdzg4yOWxG4UqOk+AG4HP8kERgaCIVCFDCynDItUkQ4kCwYHIkBBAVs9qSGKIWAdvgBaIjU2n0emM5GOT6fYBAA

Answer 1

If the date format is always the same, you can just create the string in format YYYYMMDD and then compare -

 var data = [{ Title: "Title", Url: "myUrl", publishedDate: "19/01/2021" }, { Title: "Title 2", Url: "myUrl", publishedDate: "17/12/2020" }, { Title: "Title 3", Url: "myUrl", publishedDate: "11/03/2021" }, { Title: "Title 4", Url: "myUrl", publishedDate: "11/12/2020" }] var sortedData = data.sort(function(a, b) { a = a.publishedDate.split('/').reverse().join(''); b = b.publishedDate.split('/').reverse().join(''); return a > b? 1: a < b? -1: 0; }); console.log(sortedData);

The solution here also suggests the same (as well as to use .localeCompare as an alternative)

Answer 2

You can use the Date.UTC method that accepts year, month index, day to create your dates and pass these values by parsing your input dates strings like so:

 this.state = { data: [{ Title: "Title", Url: "myUrl", publishedDate: "19/01/2021" }, { Title: "Title 2", Url: "myUrl", publishedDate: "17/12/2020" }, { Title: "Title 3", Url: "myUrl", publishedDate: "11/03/2021" }, { Title: "Title 4", Url: "myUrl", publishedDate: "11/12/2020" }]}; console.log(this.state.data.sort(function(a, b) { var c = Date.UTC(a.publishedDate.split("/")[2], a.publishedDate.split("/")[1] - 1, a.publishedDate.split("/")[0]); var d = Date.UTC(b.publishedDate.split("/")[2], b.publishedDate.split("/")[1] - 1, b.publishedDate.split("/")[0]); return c - d; }))