Sort Objects in Array by Multiple Properties

Question

I am new to js and trying to sort an array of objects by two fields - starting with the first property, and then by the second property. Both properties are numbers.

The data is:

var homes = [{
 "h_id": "3",
 "minimumorder": "12",
 "price": "17"
 }, {
 "h_id": "4",
 "minimumorder": "1",
 "price": "20"
}, {
 "h_id": "5",
 "minimumorder": "1",
 "price": "18.10"
}

There are more objects in the array, this is a simplified example. The below code ALMOST gets me there, but for the minimumorder property it puts 12 after 1 instead of after 6:

cmp = function(a, b) {
 parseFloat(a);
 parseFloat(b);
 if (a > b) return +1;
 if (a < b) return -1;
 return 0;
}
homes.sort(function(a, b) { 
 return cmp(a.minimumorder,b.minimumorder) || cmp(a.price,b.price)
})

jsFiddle here.

Any help would be HUGELY appreciated, as I've been googling and tinkering for hours trying to figure this out.

• Learner: || cmp(a.price,b.price) is an elegant fallback when minimumorder returns 0. Nice

Answer 1

You need to reassign the parsed value back to a and b:

a = parseFloat(a);
b = parseFloat(b);

Otherwise it ends up comparing strings, and 12 occurs after 1 lexically, just like the word at comes after a in the dictionary.

Updated fiddle.

Answer 2

Well,

You should use a code like this:

function sortHomes(homes)
{
 var temp_homes = new Array();
 var new_homes = new Array();
 for(var i = 0; i < homes.length; i++) temp_homes[i] = homes[i];
 var maximum = 0, minimum;
 for(i = 0; i < temp_homes.length; i++) maximum = Math.max(maximum, temp_homes.minimumorder);
 var min_price, j, k, indexes, price_indexes;
 for(i = 0; i < temp_homes.length; i++){
 minimum = maximum;
 for(j = 0; j < temp_homes.length; j++){
 minimum = Math.min(minimum, temp_homes[j].minimumorder);
 }
 indexes = getIndexes(temp_homes, minimum, "minimumorder");
 if(indexes.length == 1){
 new_homes.push(temp_homes[indexes[0]]);
 temp_homes[indexes[0]].minimumorder = maximum + 1;
 }
 else{
 for(j = 0; j < indexes.length; j++){
 min_price = maximum;
 for(k = 0; k < indexes.length; k++){
 min_price = Math.min(min_price, temp_homes[indexes[k]].price);
 }
 price_indexes = getIndexes(temp_homes, min_price, "price");
 for(k = 0; k < price_indexes.length; k++){
 new_homes.push(temp_homes[price_indexes[k]]);
 temp_homes[price_indexes[k]].price = maximum + 1;
 }
 }
 }
 }
}
function getIndexes(arr, el, name)
{
 var indexes = new Array();
 for(var i = 0; i < arr.length; i++) if(arr[i][name] == el) indexes.push(i);
 return indexes;
}

It should work. If it doesn't, please inform me about it.

Oh, and in order to sort homes, just use:

homes = sortHomes(homes);