Javascript, how do you sort an array on multiple columns?

I think what you're looking for is thenBy.js: https://github.com/Teun/thenBy.js

It allows you to use the standard Array.sort, but with firstBy().thenBy().thenBy() style.

An example can be seen here.

This is handy for alpha sorts of all sizes. Pass it the indexes you want to sort by, in order, as arguments.

Array.prototype.deepSortAlpha= function(){
    var itm, L=arguments.length, order=arguments;

    var alphaSort= function(a, b){
        a= a.toLowerCase();
        b= b.toLowerCase();
        if(a== b) return 0;
        return a> b? 1:-1;
    }
    if(!L) return this.sort(alphaSort);

    this.sort(function(a, b){
        var tem= 0,  indx=0;
        while(tem==0 && indx<L){
            itm=order[indx];
            tem= alphaSort(a[itm], b[itm]); 
            indx+=1;        
        }
        return tem;
    });
    return this;
}

var arr= [[ "Nilesh","Karmshil"], ["Pranjal","Deka"], ["Susants","Ghosh"],
["Shiv","Shankar"], ["Javid","Ghosh"], ["Shaher","Banu"], ["Javid","Rashid"]];

arr.deepSortAlpha(1,0);

Came across a need to do SQL-style mixed asc and desc object array sorts by keys.

kennebec's solution above helped me get to this:

Array.prototype.keySort = function(keys) {

keys = keys || {};

// via
// http://stackoverflow.com/questions/5223/length-of-javascript-object-ie-associative-array
var obLen = function(obj) {
    var size = 0, key;
    for (key in obj) {
        if (obj.hasOwnProperty(key))
            size++;
    }
    return size;
};

// avoiding using Object.keys because I guess did it have IE8 issues?
// else var obIx = function(obj, ix){ return Object.keys(obj)[ix]; } or
// whatever
var obIx = function(obj, ix) {
    var size = 0, key;
    for (key in obj) {
        if (obj.hasOwnProperty(key)) {
            if (size == ix)
                return key;
            size++;
        }
    }
    return false;
};

var keySort = function(a, b, d) {
    d = d !== null ? d : 1;
    // a = a.toLowerCase(); // this breaks numbers
    // b = b.toLowerCase();
    if (a == b)
        return 0;
    return a > b ? 1 * d : -1 * d;
};

var KL = obLen(keys);

if (!KL)
    return this.sort(keySort);

for ( var k in keys) {
    // asc unless desc or skip
    keys[k] = 
            keys[k] == 'desc' || keys[k] == -1  ? -1 
          : (keys[k] == 'skip' || keys[k] === 0 ? 0 
          : 1);
}

this.sort(function(a, b) {
    var sorted = 0, ix = 0;

    while (sorted === 0 && ix < KL) {
        var k = obIx(keys, ix);
        if (k) {
            var dir = keys[k];
            sorted = keySort(a[k], b[k], dir);
            ix++;
        }
    }
    return sorted;
});
return this;
};

sample usage:

var obja = [
  {USER:"bob",  SCORE:2000, TIME:32,    AGE:16, COUNTRY:"US"},
  {USER:"jane", SCORE:4000, TIME:35,    AGE:16, COUNTRY:"DE"},
  {USER:"tim",  SCORE:1000, TIME:30,    AGE:17, COUNTRY:"UK"},
  {USER:"mary", SCORE:1500, TIME:31,    AGE:19, COUNTRY:"PL"},
  {USER:"joe",  SCORE:2500, TIME:33,    AGE:18, COUNTRY:"US"},
  {USER:"sally",    SCORE:2000, TIME:30,    AGE:16, COUNTRY:"CA"},
  {USER:"yuri", SCORE:3000, TIME:34,    AGE:19, COUNTRY:"RU"},
  {USER:"anita",    SCORE:2500, TIME:32,    AGE:17, COUNTRY:"LV"},
  {USER:"mark", SCORE:2000, TIME:30,    AGE:18, COUNTRY:"DE"},
  {USER:"amy",  SCORE:1500, TIME:29,    AGE:19, COUNTRY:"UK"}
];

var sorto = {
  SCORE:"desc",TIME:"asc", AGE:"asc"
};

obja.keySort(sorto);

yields the following:

 0: {     USER: jane;     SCORE: 4000;    TIME: 35;       AGE: 16;    COUNTRY: DE;   }
 1: {     USER: yuri;     SCORE: 3000;    TIME: 34;       AGE: 19;    COUNTRY: RU;   }
 2: {     USER: anita;    SCORE: 2500;    TIME: 32;       AGE: 17;    COUNTRY: LV;   }
 3: {     USER: joe;      SCORE: 2500;    TIME: 33;       AGE: 18;    COUNTRY: US;   }
 4: {     USER: sally;    SCORE: 2000;    TIME: 30;       AGE: 16;    COUNTRY: CA;   }
 5: {     USER: mark;     SCORE: 2000;    TIME: 30;       AGE: 18;    COUNTRY: DE;   }
 6: {     USER: bob;      SCORE: 2000;    TIME: 32;       AGE: 16;    COUNTRY: US;   }
 7: {     USER: amy;      SCORE: 1500;    TIME: 29;       AGE: 19;    COUNTRY: UK;   }
 8: {     USER: mary;     SCORE: 1500;    TIME: 31;       AGE: 19;    COUNTRY: PL;   }
 9: {     USER: tim;      SCORE: 1000;    TIME: 30;       AGE: 17;    COUNTRY: UK;   }
 keySort: {  }

(using a print function from here)

here is a jsbin example.

edit: cleaned up and posted as mksort.js on github.

function multiSort() {

    var args =$.makeArray( arguments ),
        sortOrder=1, prop='', aa='',  b='';

    return function (a, b) {

       for (var i=0; i<args.length; i++){

         if(args[i][0]==='-'){
            prop=args[i].substr(1)
            sortOrder=-1
         }
         else{sortOrder=1; prop=args[i]}

         aa = a[prop].toLowerCase()
         bb = b[prop].toLowerCase()

         if (aa < bb) return -1 * sortOrder;
         if (aa > bb) return 1 * sortOrder;

       }

       return 0
    }

}
empArray.sort(multiSort( 'lastname','firstname')) Reverse with '-lastname'

You could concat the 2 variables together into a sortkey and use that for your comparison.

list.sort(function(a,b){
   var aCat = a.var1 + a.var2;
   var bCat = b.var1 + b.var2;
   return (aCat > bCat ? 1 : aCat < bCat ? -1 : 0);
});