Sorting an Array of JavaScript Objects a Specific Order (using existing function)

Question

Given an array of objects:

{
    key: "a",
    value: 42
},
{
    key: "d",
    value: 28
},
{
    key: "c",
    value: 92
},
{
    key: "b",
    value: 87
}

and an array of keys:

["c", "a", "b", "d"]

Is there a ECMAScript function or a 3rd-party JavaScript library that lets you sort - in one line/function call - the first array of objects, to match the order of the keys specified in the second array, such that the result is:

{
    key: "c",
    value: 92
},
{
    key: "a",
    value: 42
},
{
    key: "b",
    value: 87
},
{
    key: "d",
    value: 28
}

Other questions that provide a function or algorithm:

• Javascript - sort array based on another array - Stack Overflow
• javascript - How do I sort an array of objects based on the ordering of another array? - Stack Overflow

Similar/related questions:

• Sorting an Array of Objects in PHP In a Specific Order
• php - Sort array of objects

Answer 1

Just use indexOf to convert the key to the correct order:

var order = ["c", "a", "b", "d"];
_.sortBy(arr, function(obj){ 
    return _.indexOf(order, obj.key);
});

Fiddle

If there are a lot of keys, then it would be advantageous to make a hash-map out of the array, like:

var order = ["c", "a", "b", "d"];
var orderMap = {};
_.each(order, function(i) { orderMap[i] = _.indexOf(order, i); });

This makes the key-sorting lookup constant time rather than O(n). (Fiddle)