Sort hash ascending by value using sortBy in javascript

Question

I used sortBy function in underscore.js library.

I have hash, and I tried to sort it by value as the following:

var obj = {x: 2, y: 6, z: 1, q: 4};
_.sortBy(obj)

But the output is as the following:

[1, 2, 4, 6]

But I need to sort it, and return keys with value as the following:

{z: 1, x: 2, q: 4, y: 6}

How can I return sorted hash using sortBy ?

I noticed that sortBy function return list, so is there another good solution to sort hash or I need to implement function return sorted hash ?

Answer 1

There's no such thing as a sorted hash (object) in JavaScript. What you can do is put the keys in an array, iterate that and use the keys to access the object properties.

var keys = Object.keys(obj);
keys.sort(function(a, b) {
    return obj[a] - obj[b]
});

keys.forEach(function(k) {
   console.log(obj[k]);
});

Answer 2

Related to @Ragnar answer. I got solution to solve the question. And return sorted hash.

Ascending Order

function getSortedHash(inputHash){
  var resultHash = {};

  var keys = Object.keys(inputHash);
  keys.sort(function(a, b) {
    return inputHash[a] - inputHash[b]
  }).forEach(function(k) {
    resultHash[k] = inputHash[k];
  });
  return resultHash;
}

Descending Order

function getSortedHash(inputHash){
  var resultHash = {};

  var keys = Object.keys(inputHash);
  keys.sort(function(a, b) {
    return inputHash[a] - inputHash[b]
  }).reverse().forEach(function(k) {
    resultHash[k] = inputHash[k];
  });
  return resultHash;
}

Answer 3

In addition, if you want to return the array in descending order, you can use reverse() function:

var obj = {x: 2, y: 6, z: 1, q: 4};

var keys = Object.keys(obj);
keys.sort(function(a, b) {
    return obj[a] - obj[b]
}).reverse().forEach(function(k) {
   console.log(obj[k]);
});

or just like this (thanks to @muistooshort):

var obj = {x: 2, y: 6, z: 1, q: 4};

var keys = Object.keys(obj);
keys.sort(function(a, b) {
    return obj[b] - obj[a]   //inverted comparison
}).forEach(function(k) {
   console.log(obj[k]);
});