Grouping Objects In Array Based On Property Name

Question

I have an array with a list of objects:

var myArray = [
    {"cartItems": {"paramA1": 25, "paramA2": 35}},
    {"cartShippingCost": {"paramB1": 4, "paramB2": 152, "paramB3": 536, "paramB4": 56}},
    {"cartSpecialRequirements": {"paramC1": 432}},
    {"cartPostage": {"paramD1": 56, "paramD2": 6537}},
    {"uid": {"paramE1": 545}},
    {"tel": 7778798548}
];

How can i loop through the above and group objects that contain 'cart' and ones that don't?

I know i need to create 2 temp obj's e.g.

var cartObj;
var nonCartObj;

And perform a .push in to each of these if the condition is met.

Tried:

for(var i in myArray) { 
    if (i == 'cart') {
        console.log('cart match found');
    }
}

Update:

Using Object.keys always hitting else case:

var key = Object.keys(item);

if (key.indexOf("cart") !== -1) {
    alert(key + " contains cart");
} else {
    alert(key + " doesnt contain cart");
}

Calvin Belden · Accepted Answer · 2016-03-10 18:16:42Z

3

You can use Array.prototype.filter to create a new array where each item satisfies some condition:

var cartItems = myArray.filter(hasCartProperty);
var nonCartItems = myArray.filter(function (x) { return !hasCartProperty(x); });


// Checks to see if any of the object's keys contain the text 'cart'
function hasCartProperty(x) {
    return Object.keys(x).some(function (x) {
        return x.indexOf('cart') > -1;
    });
}

edited Mar 10, 2016 at 18:16

answered Mar 10, 2016 at 17:53

Calvin Belden

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2 Comments

Oam Psy Over a year ago

@CalvinBelden - thanks, but isnt => only available in ES6. What about ES5?

Jack Guy Over a year ago

Indeed, that was an interesting choice using it for one and not the other

Jack Guy · Accepted Answer · 2016-03-10 17:52:41Z

2

Loop through each item of the array, and then inside that loop iterate over the object keys to find what you're looking for

var result = [];
myArray.forEach(function (item) {
  for (var key in item) {
     if (key.indexOf('cart') !== -1) {
        result.push(item);
     }
  }
});

console.log(result);

answered Mar 10, 2016 at 17:52

Jack Guy

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3 Comments

Oam Psy Over a year ago

thanks, i made some progrss, and instead of your for loop, i used Object.keys... any pros or cons over each?

Jack Guy Over a year ago

@OamPsy Object.keys is better because it won't iterate over properties like toString. I just opted to keep it simple. :)

Oam Psy Over a year ago

ive added an update using Object.keys, but it always hits the else statement. Ill mark the above as the answer regardless, but any help on Object.keys would be appreciated.

Jack A. · Accepted Answer · 2016-03-10 17:58:41Z

The JavaScript Array object has a filter function that can be used for this.

The tricky part is the function that performs the filtering. One way to do that is to iterate the keys in the objects to detect which ones contain "cart" keys.

var myArray = [
    {"cartItems": {"paramA1": 25, "paramA2": 35}},
    {"cartShippingCost": {"paramB1": 4, "paramB2": 152, "paramB3": 536, "paramB4": 56}},
    {"cartSpecialRequirements": {"paramC1": 432}},
    {"cartPostage": {"paramD1": 56, "paramD2": 6537}},
    {"uid": {"paramE1": 545}},
    {"tel": 7778798548}
];

var cartObj = myArray.filter(function (x) { return isCart(x); });
var nonCartObj = myArray.filter(function (x) { return !isCart(x); });

console.log("cart count = " + cartObj.length + ", non-cart count = " + nonCartObj.length);

function isCart(x) {
  for (var key in x) {
    if (x.hasOwnProperty(key) && key.startsWith("cart")) {
      return true;
    }
  }
  return false;
}

Nina Scholz · Accepted Answer · 2016-03-10 18:10:43Z

A solution with one loop without Array#filter().

var myArray = [{ "cartItems": { "paramA1": 25, "paramA2": 35 } }, { "cartShippingCost": { "paramB1": 4, "paramB2": 152, "paramB3": 536, "paramB4": 56 } }, { "cartSpecialRequirements": { "paramC1": 432 } }, { "cartPostage": { "paramD1": 56, "paramD2": 6537 } }, { "uid": { "paramE1": 545 } }, { "tel": 7778798548 }],
    grouped = function (array) {
        var r = { cart: [], nonCart: [] };
        array.forEach(function (a) {
            Object.keys(a).some(function (k) {
                if (k.indexOf('cart') === 0) {
                    return r.cart.push(a);
                }
            }) || r.nonCart.push(a);
        });
        return r;
    }(myArray);

document.write('<pre>' + JSON.stringify(grouped, 0, 4) + '</pre>');

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