Simple logic in javascript

Question

I have four variables of type integer -

var tip_1, tip_2, tip_3, tip_4;

The value of these variables are getting fill by some other logic which is always between 1 to 10. I need to maintain a hash with variable name as "key" and value as "value" by following these rules -

1. The variable with MAX value should be the first element in the hash and so on. e.g. if tip_1 = 4, tip_2 = 1, tip_3 = 2, tip_4 = 10 then hash should be something like, Hash = {tip_4, 10} {tip_1, 4} {tip_3, 2} {tip_1, 1}

2. In case of tie following order should be considered - tip_1 > tip_2 > tip_3 > tip_4;

Answer 1

It's a lot easier to do if you make a real array out of your tips:

var tip_1 = 4, tip_2 = 1, tip_3 = 2, tip_4 = 10;

// create an array so we can sort it
var tips = [
  { key: 'tip_1', value: tip_1 }, 
  { key: 'tip_2', value: tip_2 }, 
  { key: 'tip_3', value: tip_3 }, 
  { key: 'tip_4', value: tip_4 }, 
];

tips.sort(function (a, b) {
  // sort value descending
  if (a.value < b.value) return 1;
  if (a.value > b.value) return -1;
  // if the values are equal, sort by key.
  return a.key > b.key ? 1 : b.key < a.key ? -1 : 0; 
});

// tips is now:
// [{key:"tip_4", value:10}, {key:"tip_1", value:4}, {key:"tip_2", value:2}, {key:"tip_3", value:2}]

// loop over the tips
for (var tip, i=0; tip = tips[i]; i++) {
  console.log(tip.key+": "+tip.value);
}

// Outputs:
// tip_4: 10
// tip_1: 4
// tip_3: 2
// tip_2: 1

Answer 2

You can always build your custom objects to retain all information instead of encoding them in indices. Makes sorting easier too.

function Tip(type, value) {
    this.type = type;
    this.value = value;
}

var tips = [];

tips.push(new Tip(3, 4));
tips.push(new Tip(2, 4));
tips.push(new Tip(1, 3));
tips.push(new Tip(4, 10));

tips.sort(function(a, b) {
    // sort first by value, and if equal, then by type (index)
    return (b.value - a.value) || (a.type - b.type);    
});

console.log(tips); // 4=>10​, 2=>4, 3=>4, 1=>3​​​​​​​​​​​​​​​​​

Updated the example.