Does JQuery have a sort_by function similar to Ruby's

Question

So given a list of items like so:

item_1 = {id:1, categories: {"category_A" => 1, "category_B" => {"sub_category_A" => 3, "sub_category_B" => 1}}}
item_2 = {id:2, categories: {"category_B" => {"sub_category_A" => 1, "sub_category_B" => 2}}}

Where the numeric value is that items order in a given sub or main category. Now, given a sub or main category, I want to sort the items by the order number. In Ruby I'd write...

# Given category_B and sub_category_A
items.sort_by { |i| i.categories["category_B"]["sub_category_A"] }

# which would return...
[item_2, item_1]

Also want to add, the key is if an item does NOT have the relevant passed category_B and sub_category_A, it should be excluded entirely from output.

Answer 1

You don't need jQuery; JavaScript arrays have a filter() function you can use to limit yourself to valid items and a sort() function that can take a comparing function as its argument:

var item_1 = {
    id:1, 
    categories: {
        "category_A" : 1,
        "category_B" : {
            "sub_category_A" : 3,
            "sub_category_B" : 1
        }
    }
};
var item_2 = {
    id:2,
    categories: {
        "category_B" : {
            "sub_category_A" : 1,
            "sub_category_B" : 2
        }
    }
};

var item_3 = {
    id: 3,
    categories : {
        "category_A" : 2
    }
};

[item_1,item_2,item_3].filter(function(entry) {
  return entry.categories.category_B;}).sort(function(left, right) {
  return left.categories["category_B"]["sub_category_A"] -
    right.categories["category_B"]["sub_category_A"]
});

// or in the more readable ES6 style
[item_1,item_2,item_3]
    .filter((entry) => entry.categories.category_B)
    .sort((left, right) =>  left.categories["category_B"]["sub_category_A"] - right.categories["category_B"]["sub_category_A"]
);

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort

Answer 2

You can use Array#Sort in JavaScript.

a.categories["category_B"]["sub_category_A"] - b.categories["category_B"]["sub_category_A"]

Is the comparison of 2 elements in Array.

UPDATE : to excluded from the output. You can use Array#filter it before sorting

Let's see my example

 var arr = [{ id:1, categories: { "category_A" : 1, "category_B" : { "sub_category_A" : 3, "sub_category_B" : 1 } } },{ id:3, categories: { "category_C" : { "sub_category_A" : 1, "sub_category_B" : 2 } } },{ id:2, categories: { "category_B" : { "sub_category_A" : 1, "sub_category_B" : 2 } } }]; var result = arr.filter(a => a.categories["category_B"]) .sort((a, b) => { return a.categories["category_B"]["sub_category_A"] - b.categories["category_B"]["sub_category_A"]; }) console.log(result); 

Answer 3

Neither ECMAScript nor jQuery have sortBy , but LoDash does and so does Underscore .

It's also not hard to supply your own:

 Array.prototype.sortBy = function sortBy(keyFn) { const compare = (a, b) => a > b ? 1 : (a < b ? -1 : 0); return this. map(el => [keyFn(el), el]). sort(([a, ], [b, ]) => compare(a, b)). map(([, el]) => el); }; const item1 = { id: 1, categories: { category_A: 1, category_B: { sub_category_A: 3, sub_category_B: 1 }}}; const item2 = { id: 2, categories: { category_B: { sub_category_A: 1, sub_category_B: 2 }}}; const sorted = [item1, item2].sortBy(el => el.categories.category_B.sub_category_A); console.log(sorted);