Sort javascript array null value always at bottom

Question

Hey i am using slickgrid plugin and there i have function sortNumeric to sort data in order

function sorterNumeric(a, b) {
      var x = (isNaN(a[sortcol]) || a[sortcol] === "" || a[sortcol] === null) ? -99e+10 : parseFloat(a[sortcol]);
      var y = (isNaN(b[sortcol]) || b[sortcol] === "" || b[sortcol] === null) ? -99e+10 : parseFloat(b[sortcol]);
      return sortdir * (x === y ? 0 : (x > y ? 1 : -1));
    }

Can someone help me to extend this sorting, so null values comes always at last place.

Instead of -99e+10 (which might be the smallest number you can imagine), one should use -Infinity — Bergi
– Bergi, Commented May 2, 2017 at 9:59
by always i mean when you sort in asc should be 1,2,3 NULL at end or desc 5,4,3,2,1 NULL at the end also. Data are just some random numbers — vladimirProp
– vladimirProp, Commented May 2, 2017 at 10:00

Nina Scholz · Accepted Answer · 2017-05-02 11:15:09Z

3

You could use the result of the comparison as value for the needed delta.

In SlickGrid, you get the sort order with the property sortAsc of the wanted cols to sort. then just use the closure over the sorting direction.

function sortFn(sortAsc) {
    return function (a, b) {
        return (a[sortcol] === null) - (b[sortcol] === null) || (sortAsc || -1) * (a[sortcol] - b[sortcol]);
    }
}

var array = [{ a: 1 }, { a: 3 }, { a: 2 }, { a: 8 }, { a: null }, { a: 42 }, { a: null }],
    sortcol = 'a';

array.sort(sortFn(true));  // asc
console.log(array);

array.sort(sortFn(false)); // desc
console.log(array);

.as-console-wrapper { max-height: 100% !important; top: 0; }

edited May 2, 2017 at 11:15

answered May 2, 2017 at 9:59

Nina Scholz

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4 Comments

cezar Over a year ago

Nice! Very elegant solution with plain JavaScript.

vladimirProp Over a year ago

can you help me to overwrite my function because is slickgrid plugin function

vladimirProp Over a year ago

but there is one function to sort asc or desc

Nina Scholz Over a year ago

@vladimirProp, you could utilize the given sortorder of the wanted column.

François Maturel · Accepted Answer · 2017-05-02 10:45:18Z

0

You can use following code:

var sortcol = "num";
var sortdir = -1;

function sorterNumeric(a, b) {
    var x = (isNaN(a[sortcol]) || !a[sortcol]) ? 99e+10 * sortdir : parseFloat(a[sortcol]);
    var y = (isNaN(b[sortcol]) || !b[sortcol]) ? 99e+10 * sortdir : parseFloat(b[sortcol]);
    return x > y ? 1 * sortdir : -1 * sortdir;
}

var arr = [{ num: 1 }, { num: 3 }, { num: null }, { num: 7 }, { num: 2 } ]

edited May 2, 2017 at 10:45

François Maturel

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answered May 2, 2017 at 10:12

Quickitdotnet

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3 Comments

Bergi Over a year ago

Don't forget to return 0!

vladimirProp Over a year ago

where to return 0

Abbas Kararawala Over a year ago

please don't just show the code. give explanation as how it works

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