ag-grid Angular custom sort parameters showing as undefined - sorting

Question

I've set the following comparator on columnDef
...
comparator: (date1: string, date2: string): number => this.dateComparator(date1,date2),
...
and have a custom function to sort strings as dates as below
dateComparator(date1: string, date2: string): number {
const d1 = new Date(date1);
const d2 = new Date(date2);
//custom logic and return..
}
However, the date1 and date2 parameters are undefined. can someone help with this please.

Answer 1

I have written the same comparator
export function dateComparator(date1: string, date2: string) {
const date1Number = date1 ? new Date(date1).getTime() : null;
const date2Number = date2 ? new Date(date2).getTime() : null;
if (date1Number === null && date2Number === null) {
return 0;
}
if (date1Number === null) {
return -1;
}
if (date2Number === null) {
return 1;
}
return date1Number - date2Number;
}
But if you change your value of the cell in some cases (from date to string - like in my case if date is null I am showinng 'Never Logged' then we should replace it) - and showing just a string you can use the next comparator:
export function dateComparator(date1: string, date2: string) {
const neverLog = 'Never Logged';
const date1Number = date1 === neverLog ? null : new Date(date1).getTime();
const date2Number = date2 === neverLog ? null : new Date(date2).getTime();
if (date1Number === null && date2Number === null) {
return 0;
}
if (date1Number === null) {
return -1;
}
if (date2Number === null) {
return 1;
}
return date1Number - date2Number; }

Answer 2

if you are not sure whether the date value which is being passed in the comparator is valid string or not then you can check it first and sanitize it before comparing.
function dateComparator(date1, date2) {
var date1Number = validateDateinput(date1);
var date2Number = validateDateinput(date2);
if (date1Number === null && date2Number === null) {
return 0;
}
if (date1Number === null) {
return -1;
}
if (date2Number === null) {
return 1;
}
//custom logic and return..
return date1Number - date2Number;
}
function validateDateinput(date) {
// handle null and undefined values. add more logic here as per use case
if (date === undefined || date === null) {
return null;
}
//string is valid to create date
return new Date(date);
}