Converting alphabetic compare function to a date compare function

Question

I am using a Mat List to display a lot of data. The mat list is used to order the data depending on the column values.

I have this working compare function which sorts alphabetic or numerical, depending of the input type:

function compare(a, b, isAsc) {
  return (a < b ? -1 : 1) * (isAsc ? 1 : -1);
}

The table gets sorted by this function:

this.sortedData = data.sort((a, b) => {
        const isAsc = sort.direction === 'asc';
        switch (sort.active) {
            case 'OrderId':
                return compare(+a.OrderId, +b.OrderId, isAsc);
            case 'Site':
                return compare(a.Site, b.Site, isAsc);
            case 'OrderDate':
                return compare(a.OrderDate, b.OrderDate, isAsc);
            case 'Email':
                return compare(a.Email, b.Email, isAsc);
            case 'Phone':
                return compare(a.Phone, b.Phone, isAsc);
            case 'FullName':
                return compare(a.FullName, b.FullName, isAsc);
            default:
                return 0;
        }
    });

This is working as intended, however I want to sort the date property the same way, in a chronological way. How can I do that? I basically just need a working compare function, which supports 'isAsc' - is True for ascending and false for descending.

The a.Orderdate variable can be parsed to a date with

new Date(a.OrderDate)

Since it is a date converted to a string.

btw, your sort does not respect equal values. i suggest to use the return values of smaller zero, zero and greater than zero for sorting. then i would take the sort function and take a closure over ht wanted sort order. — Nina Scholz, May 22 '18 at 13:25
in which form do you have the date? as iso or as epoch time? — Nina Scholz, May 22 '18 at 14:26
'26-02-2018 22:51' for example. Can be parsed to a Date object if needed. — Jonas Praem, May 22 '18 at 14:44
No it will sort on day first, then month, then year. Normally you would want it the other way around — Jonas Praem, May 22 '18 at 14:49
oh sorry. you are right, you need a wrapper for getting a comparable string. — Nina Scholz, May 22 '18 at 14:51
Let us [continue this discussion in chat](https://chat.stackoverflow.com/rooms/171554/discussion-between-nina-scholz-and-jonas-praem). — Nina Scholz, May 22 '18 at 14:54
@JonasPraem—not reliably by `new Date('26-02-2018 22:51')` though, see [*Why does Date.parse give incorrect results?*](https://stackoverflow.com/questions/2587345/why-does-date-parse-give-incorrect-results) — RobG, May 23 '18 at 11:09

Converting alphabetic compare function to a date compare function

0 Answers0